diff --git a/control_plane/authoring/book_state.py b/control_plane/authoring/book_state.py
index 1df937b..ac47806 100644
--- a/control_plane/authoring/book_state.py
+++ b/control_plane/authoring/book_state.py
@@ -648,9 +648,9 @@ class BookStateService:
         )
         if not validation["valid"]:
             raise ValueError("book state is not approval-valid: " + "; ".join(validation["errors"]))
-        parent_id = _value(locked, "parent_id")
         current_id = _value(work, "current_book_state_id")
-        if parent_id != current_id:
+        approved_base_id = self._approved_base_id(locked)
+        if approved_base_id != current_id:
             raise ValueError("book state parent is stale relative to the work's approved state")
         if force and not notes.strip():
             raise ValueError("forced approval requires notes")
@@ -684,6 +684,18 @@ class BookStateService:
         self._write_artifacts(locked)
         return locked
 
+    @staticmethod
+    def _approved_base_id(state: BookStateVersion) -> Any:
+        ancestor_id = state.parent_id
+        while ancestor_id:
+            ancestor = BookStateVersion.objects.select_for_update().only(
+                "id", "parent_id", "status"
+            ).get(pk=ancestor_id)
+            if ancestor.status == BookStateStatus.APPROVED:
+                return ancestor.id
+            ancestor_id = ancestor.parent_id
+        return None
+
     @transaction.atomic
     def reject(
         self, state: BookStateVersion, *, actor: str = "", notes: str = ""
diff --git a/tests/test_book_authoring_state.py b/tests/test_book_authoring_state.py
index 098ae75..10f720c 100644
--- a/tests/test_book_authoring_state.py
+++ b/tests/test_book_authoring_state.py
@@ -230,6 +230,24 @@ def test_approval_requires_all_reviews_and_rejects_stale_parent(work: Work) -> N
         service.approve(child)
 
 
+def test_approval_allows_review_revisions_before_first_approved_state(work: Work) -> None:
+    service = BookStateService(FakeReviewRouter())
+    first = service.create(work=work, content=book_content(1))
+    second_content = deepcopy(first.content)
+    second_content["open_questions"] = ["What must the pilot verify?"]
+    second = service.revise(first, content=second_content)
+    third_content = deepcopy(second.content)
+    third_content["open_questions"] = ["What evidence resolves the review finding?"]
+    third = service.revise(second, content=third_content)
+    make_review_ready(third)
+
+    approved = service.approve(third, actor="editor")
+
+    work.refresh_from_db()
+    assert approved.status == BookStateStatus.APPROVED
+    assert work.current_book_state == approved
+
+
 def test_review_routes_structure_and_continuity_to_distinct_capabilities(work: Work) -> None:
     router = FakeReviewRouter()
     service = BookStateService(router)