diff --git a/crates/api/Cargo.toml b/crates/api/Cargo.toml
index 5eda5af..a50774f 100644
--- a/crates/api/Cargo.toml
+++ b/crates/api/Cargo.toml
@@ -8,6 +8,11 @@ rust-version.workspace = true
 axum.workspace = true
 serde.workspace = true
 utoipa.workspace = true
+time.workspace = true
+tower-sessions.workspace = true
+tower-sessions-sqlx-store.workspace = true
+sqlx.workspace = true
+auth = { path = "../auth" }
 db = { path = "../db" }
 domain = { path = "../domain" }
 
@@ -17,3 +22,4 @@ tower.workspace = true
 http-body-util.workspace = true
 serde_json.workspace = true
 sqlx.workspace = true
+auth = { path = "../auth" }
diff --git a/crates/api/src/admin.rs b/crates/api/src/admin.rs
new file mode 100644
index 0000000..593fc60
--- /dev/null
+++ b/crates/api/src/admin.rs
@@ -0,0 +1,177 @@
+//! Admin (authenticated) surface: login/logout/session, user listing, and publishing.
+
+use auth::{AuthUser, Authorized, ManageUsers, PublishObjects};
+use axum::{
+    Json, Router,
+    extract::{Path, State},
+    http::StatusCode,
+    routing::{get, post},
+};
+use domain::{AuditActor, ObjectId, Visibility};
+use serde::{Deserialize, Serialize};
+use tower_sessions::Session;
+use utoipa::ToSchema;
+
+use crate::AppState;
+
+/// Credentials for password login.
+#[derive(Deserialize, ToSchema)]
+pub(crate) struct LoginRequest {
+    pub email: String,
+    pub password: String,
+}
+
+/// A user as exposed on the admin surface (no password material).
+#[derive(Serialize, ToSchema)]
+pub(crate) struct UserView {
+    pub id: String,
+    pub email: String,
+    pub role: String,
+}
+
+/// Desired visibility for a publish/unpublish request.
+#[derive(Deserialize, ToSchema)]
+pub(crate) struct VisibilityRequest {
+    #[schema(value_type = String)]
+    pub visibility: Visibility,
+}
+
+/// Log in with email + password. On success establishes a session (Set-Cookie) and
+/// returns 204; on failure 401 with no detail (no user enumeration).
+#[utoipa::path(
+    post,
+    path = "/api/admin/login",
+    request_body = LoginRequest,
+    responses((status = 204, description = "Logged in"), (status = 401, description = "Invalid credentials"))
+)]
+pub(crate) async fn login(
+    State(state): State<AppState>,
+    session: Session,
+    Json(req): Json<LoginRequest>,
+) -> Result<StatusCode, StatusCode> {
+    let normalized = req.email.trim().to_lowercase();
+
+    let credentials = db::users::credentials_by_email(state.db.pool(), &normalized)
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    let verified = match &credentials {
+        Some((_, hash)) => auth::verify_password(&req.password, hash),
+        None => {
+            auth::verify_dummy(&req.password);
+            false
+        }
+    };
+
+    if !verified {
+        return Err(StatusCode::UNAUTHORIZED);
+    }
+
+    let (user, _) = credentials.expect("verified implies Some");
+
+    auth::establish_session(&session, user.id, &user.email, user.role)
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    Ok(StatusCode::NO_CONTENT)
+}
+
+/// Log out: clear the session.
+#[utoipa::path(post, path = "/api/admin/logout", responses((status = 204, description = "Logged out")))]
+pub(crate) async fn logout(session: Session) -> Result<StatusCode, StatusCode> {
+    session
+        .flush()
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    Ok(StatusCode::NO_CONTENT)
+}
+
+/// The current authenticated user.
+#[utoipa::path(get, path = "/api/admin/me", responses((status = 200, body = UserView), (status = 401)))]
+pub(crate) async fn me(user: AuthUser) -> Json<UserView> {
+    Json(UserView {
+        id: user.id.to_string(),
+        email: user.email.as_str().to_owned(),
+        role: user.role.as_str().to_owned(),
+    })
+}
+
+/// List all users (Admin only).
+#[utoipa::path(get, path = "/api/admin/users", responses((status = 200, body = [UserView]), (status = 401), (status = 403)))]
+pub(crate) async fn list_users(
+    _auth: Authorized<ManageUsers>,
+    State(state): State<AppState>,
+) -> Result<Json<Vec<UserView>>, StatusCode> {
+    let users = db::users::list_users(state.db.pool())
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    Ok(Json(
+        users
+            .into_iter()
+            .map(|u| UserView {
+                id: u.id.to_string(),
+                email: u.email.as_str().to_owned(),
+                role: u.role.as_str().to_owned(),
+            })
+            .collect(),
+    ))
+}
+
+/// Change an object's visibility (publish/unpublish). Requires `PublishObjects`.
+#[utoipa::path(
+    post,
+    path = "/api/admin/objects/{id}/visibility",
+    params(("id" = String, Path, description = "Object id (UUID)")),
+    request_body = VisibilityRequest,
+    responses(
+        (status = 204, description = "Visibility changed"),
+        (status = 401), (status = 403),
+        (status = 404, description = "No such object"),
+        (status = 409, description = "Illegal visibility transition")
+    )
+)]
+pub(crate) async fn set_visibility(
+    _auth: Authorized<PublishObjects>,
+    State(state): State<AppState>,
+    Path(id): Path<String>,
+    Json(req): Json<VisibilityRequest>,
+) -> Result<StatusCode, StatusCode> {
+    let object_id = id.parse::<ObjectId>().map_err(|_| StatusCode::NOT_FOUND)?;
+
+    let mut tx = state
+        .db
+        .pool()
+        .begin()
+        .await
+        .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+    // TODO(#7): record the per-user actor (AuthUser carries the id) once auth-event
+    // auditing lands; System for now.
+    let result =
+        db::catalog::set_visibility(&mut tx, AuditActor::System, object_id, req.visibility).await;
+
+    match result {
+        Ok(()) => {
+            tx.commit()
+                .await
+                .map_err(|_| StatusCode::INTERNAL_SERVER_ERROR)?;
+
+            Ok(StatusCode::NO_CONTENT)
+        }
+        Err(db::catalog::VisibilityError::ObjectNotFound) => Err(StatusCode::NOT_FOUND),
+        Err(db::catalog::VisibilityError::Illegal(_)) => Err(StatusCode::CONFLICT),
+        Err(db::catalog::VisibilityError::Db(_)) => Err(StatusCode::INTERNAL_SERVER_ERROR),
+    }
+}
+
+/// Admin routes, parameterized over [`AppState`].
+pub(crate) fn routes() -> Router<AppState> {
+    Router::new()
+        .route("/api/admin/login", post(login))
+        .route("/api/admin/logout", post(logout))
+        .route("/api/admin/me", get(me))
+        .route("/api/admin/users", get(list_users))
+        .route("/api/admin/objects/{id}/visibility", post(set_visibility))
+}
diff --git a/crates/api/src/lib.rs b/crates/api/src/lib.rs
index ab7c81b..aeea91b 100644
--- a/crates/api/src/lib.rs
+++ b/crates/api/src/lib.rs
@@ -1,11 +1,16 @@
 //! HTTP API: router, handlers, and OpenAPI document.
 
+mod admin;
 mod health;
 mod openapi;
 mod public;
 
 use axum::Router;
 use db::Db;
+use time::Duration;
+use tower_sessions::cookie::SameSite;
+use tower_sessions::{Expiry, SessionManagerLayer};
+use tower_sessions_sqlx_store::PostgresStore;
 
 /// Shared application state passed to handlers.
 #[derive(Clone)]
@@ -14,13 +19,34 @@ pub struct AppState {
     pub db: Db,
     /// User-facing product name (from config). Never hardcoded.
     pub app_name: String,
+    /// Whether the session cookie carries the `Secure` attribute (default true;
+    /// disable only for plain-HTTP self-hosting).
+    pub cookie_secure: bool,
 }
 
 /// Build the application router from shared state.
 pub fn build_app(state: AppState) -> Router {
+    let store = PostgresStore::new(state.db.pool().clone());
+
+    let session_layer = SessionManagerLayer::new(store)
+        .with_name("id")
+        .with_http_only(true)
+        .with_secure(state.cookie_secure)
+        .with_same_site(SameSite::Strict)
+        .with_expiry(Expiry::OnInactivity(Duration::hours(8)));
+
     Router::new()
         .merge(health::routes())
         .merge(openapi::routes())
         .merge(public::routes())
+        .merge(admin::routes())
+        .layer(session_layer)
         .with_state(state)
 }
+
+/// Create the session store's table if absent. Run once at startup (and in tests
+/// before exercising auth). Separate from `Db::migrate` — the session library's own
+/// bookkeeping table.
+pub async fn migrate_sessions(db: &Db) -> Result<(), sqlx::Error> {
+    PostgresStore::new(db.pool().clone()).migrate().await
+}
diff --git a/crates/api/src/openapi.rs b/crates/api/src/openapi.rs
index fcdc6d2..ae77ae0 100644
--- a/crates/api/src/openapi.rs
+++ b/crates/api/src/openapi.rs
@@ -1,16 +1,29 @@
 use axum::{Json, Router, extract::State, routing::get};
 use utoipa::OpenApi;
 
-use crate::{AppState, health, public};
+use crate::{AppState, admin, health, public};
 
 #[derive(OpenApi)]
 #[openapi(
-    paths(health::live, health::ready, public::list_objects, public::get_object),
+    paths(
+        health::live,
+        health::ready,
+        public::list_objects,
+        public::get_object,
+        admin::login,
+        admin::logout,
+        admin::me,
+        admin::list_users,
+        admin::set_visibility
+    ),
     components(schemas(
         health::Live,
         health::Ready,
         public::PublicView,
-        public::PublicObjectPage
+        public::PublicObjectPage,
+        admin::LoginRequest,
+        admin::UserView,
+        admin::VisibilityRequest
     )),
     info(title = "Collection Management System", version = "0.0.0")
 )]
@@ -20,7 +33,9 @@ struct ApiDoc;
 /// product name is never hardcoded.
 async fn openapi_json(State(state): State<AppState>) -> Json<utoipa::openapi::OpenApi> {
     let mut doc = ApiDoc::openapi();
+
     doc.info.title = state.app_name.clone();
+
     Json(doc)
 }
 
diff --git a/crates/api/tests/admin.rs b/crates/api/tests/admin.rs
new file mode 100644
index 0000000..4bb918e
--- /dev/null
+++ b/crates/api/tests/admin.rs
@@ -0,0 +1,240 @@
+use api::{AppState, build_app, migrate_sessions};
+use axum::body::Body;
+use axum::http::{Request, StatusCode, header};
+use db::{catalog, users};
+use domain::{AuditActor, Email, NewUser, ObjectInput, Role, Visibility};
+use http_body_util::BodyExt;
+use sqlx::PgPool;
+use tower::ServiceExt;
+
+fn state(pool: PgPool) -> AppState {
+    AppState {
+        db: db::Db::from_pool(pool),
+        app_name: "Test".into(),
+        cookie_secure: false,
+    }
+}
+
+async fn seed_user(pool: &PgPool, email: &str, password: &str, role: Role) {
+    let db = db::Db::from_pool(pool.clone());
+    let mut tx = db.pool().begin().await.unwrap();
+
+    users::create_user(
+        &mut tx,
+        AuditActor::System,
+        &NewUser {
+            email: Email::parse(email).unwrap(),
+            password_hash: auth::hash_password(password).unwrap(),
+            role,
+        },
+    )
+    .await
+    .unwrap();
+
+    tx.commit().await.unwrap();
+}
+
+fn login_request(email: &str, password: &str) -> Request<Body> {
+    Request::builder()
+        .method("POST")
+        .uri("/api/admin/login")
+        .header(header::CONTENT_TYPE, "application/json")
+        .body(Body::from(format!(
+            r#"{{"email":"{email}","password":"{password}"}}"#
+        )))
+        .unwrap()
+}
+
+fn session_cookie(resp: &axum::http::Response<Body>) -> String {
+    let raw = resp
+        .headers()
+        .get(header::SET_COOKIE)
+        .expect("Set-Cookie")
+        .to_str()
+        .unwrap();
+
+    raw.split(';').next().unwrap().to_owned()
+}
+
+#[sqlx::test(migrations = "../db/migrations")]
+async fn login_then_me_returns_identity(pool: PgPool) {
+    migrate_sessions(&db::Db::from_pool(pool.clone()))
+        .await
+        .unwrap();
+
+    seed_user(&pool, "admin@example.com", "s3cret-passw0rd", Role::Admin).await;
+
+    let app = build_app(state(pool));
+
+    let resp = app
+        .clone()
+        .oneshot(login_request("admin@example.com", "s3cret-passw0rd"))
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), StatusCode::NO_CONTENT);
+
+    let cookie = session_cookie(&resp);
+
+    let me = app
+        .oneshot(
+            Request::builder()
+                .uri("/api/admin/me")
+                .header(header::COOKIE, &cookie)
+                .body(Body::empty())
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(me.status(), StatusCode::OK);
+
+    let json: serde_json::Value =
+        serde_json::from_slice(&me.into_body().collect().await.unwrap().to_bytes()).unwrap();
+    assert_eq!(json["email"], "admin@example.com");
+    assert_eq!(json["role"], "admin");
+}
+
+#[sqlx::test(migrations = "../db/migrations")]
+async fn me_without_session_is_401(pool: PgPool) {
+    migrate_sessions(&db::Db::from_pool(pool.clone()))
+        .await
+        .unwrap();
+
+    let app = build_app(state(pool));
+
+    let resp = app
+        .oneshot(
+            Request::builder()
+                .uri("/api/admin/me")
+                .body(Body::empty())
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), StatusCode::UNAUTHORIZED);
+}
+
+#[sqlx::test(migrations = "../db/migrations")]
+async fn wrong_password_is_401(pool: PgPool) {
+    migrate_sessions(&db::Db::from_pool(pool.clone()))
+        .await
+        .unwrap();
+
+    seed_user(&pool, "admin@example.com", "right", Role::Admin).await;
+
+    let app = build_app(state(pool));
+
+    let resp = app
+        .oneshot(login_request("admin@example.com", "wrong"))
+        .await
+        .unwrap();
+    assert_eq!(resp.status(), StatusCode::UNAUTHORIZED);
+}
+
+#[sqlx::test(migrations = "../db/migrations")]
+async fn editor_cannot_list_users_but_admin_can(pool: PgPool) {
+    migrate_sessions(&db::Db::from_pool(pool.clone()))
+        .await
+        .unwrap();
+
+    seed_user(&pool, "editor@example.com", "pw-editor-123", Role::Editor).await;
+    seed_user(&pool, "admin@example.com", "pw-admin-123", Role::Admin).await;
+
+    let app = build_app(state(pool));
+
+    let resp = app
+        .clone()
+        .oneshot(login_request("editor@example.com", "pw-editor-123"))
+        .await
+        .unwrap();
+    let editor_cookie = session_cookie(&resp);
+
+    let listed = app
+        .clone()
+        .oneshot(
+            Request::builder()
+                .uri("/api/admin/users")
+                .header(header::COOKIE, &editor_cookie)
+                .body(Body::empty())
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(listed.status(), StatusCode::FORBIDDEN);
+
+    let resp = app
+        .clone()
+        .oneshot(login_request("admin@example.com", "pw-admin-123"))
+        .await
+        .unwrap();
+    let admin_cookie = session_cookie(&resp);
+
+    let listed = app
+        .oneshot(
+            Request::builder()
+                .uri("/api/admin/users")
+                .header(header::COOKIE, &admin_cookie)
+                .body(Body::empty())
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(listed.status(), StatusCode::OK);
+}
+
+#[sqlx::test(migrations = "../db/migrations")]
+async fn editor_can_publish_via_admin_endpoint(pool: PgPool) {
+    migrate_sessions(&db::Db::from_pool(pool.clone()))
+        .await
+        .unwrap();
+
+    seed_user(&pool, "editor@example.com", "pw-editor-123", Role::Editor).await;
+
+    let db = db::Db::from_pool(pool.clone());
+    let mut tx = db.pool().begin().await.unwrap();
+
+    let id = catalog::create_object(
+        &mut tx,
+        AuditActor::System,
+        &ObjectInput {
+            object_number: "P-1".into(),
+            object_name: "vase".into(),
+            number_of_objects: 1,
+            brief_description: None,
+            current_location: None,
+            current_owner: None,
+            recorder: None,
+            recording_date: None,
+            visibility: Visibility::Internal,
+        },
+    )
+    .await
+    .unwrap();
+
+    tx.commit().await.unwrap();
+
+    let app = build_app(state(pool));
+
+    let resp = app
+        .clone()
+        .oneshot(login_request("editor@example.com", "pw-editor-123"))
+        .await
+        .unwrap();
+    let cookie = session_cookie(&resp);
+
+    let publish = app
+        .oneshot(
+            Request::builder()
+                .method("POST")
+                .uri(format!("/api/admin/objects/{id}/visibility"))
+                .header(header::COOKIE, &cookie)
+                .header(header::CONTENT_TYPE, "application/json")
+                .body(Body::from(r#"{"visibility":"public"}"#))
+                .unwrap(),
+        )
+        .await
+        .unwrap();
+    assert_eq!(publish.status(), StatusCode::NO_CONTENT);
+
+    let obj = catalog::object_by_id(db.pool(), id).await.unwrap().unwrap();
+    assert_eq!(obj.visibility, Visibility::Public);
+}
diff --git a/crates/api/tests/health.rs b/crates/api/tests/health.rs
index da40fe1..46cb9a7 100644
--- a/crates/api/tests/health.rs
+++ b/crates/api/tests/health.rs
@@ -9,6 +9,7 @@ fn state(pool: PgPool, app_name: &str) -> AppState {
     AppState {
         db: db::Db::from_pool(pool),
         app_name: app_name.to_string(),
+        cookie_secure: false,
     }
 }
 
diff --git a/crates/api/tests/public.rs b/crates/api/tests/public.rs
index a3a3c0e..d30e91b 100644
--- a/crates/api/tests/public.rs
+++ b/crates/api/tests/public.rs
@@ -11,6 +11,7 @@ fn state(pool: PgPool) -> AppState {
     AppState {
         db: db::Db::from_pool(pool),
         app_name: "Test".to_string(),
+        cookie_secure: false,
     }
 }