diff --git a/packages/core/__tests__/notebooks.test.js b/packages/core/__tests__/notebooks.test.js
index 8ba717e94..b31c2ecbc 100644
--- a/packages/core/__tests__/notebooks.test.js
+++ b/packages/core/__tests__/notebooks.test.js
@@ -4,6 +4,7 @@ import {
   TEST_NOTEBOOK,
   TEST_NOTE,
 } from "./utils";
+import { makeTopic } from "../collections/topics";
 
 beforeEach(async () => {
   StorageInterface.clear();
@@ -43,6 +44,92 @@ test("unpin a notebook", () =>
 
 test("updating notebook with empty title should throw", () =>
   notebookTest().then(async ({ db, id }) => {
-    expect(id).toBeDefined();
     await expect(db.notebooks.add({ id, title: "" })).rejects.toThrow();
   }));
+
+test("merge notebook with new topics", () =>
+  notebookTest().then(async ({ db, id }) => {
+    let notebook = db.notebooks.notebook(id);
+
+    const newNotebook = { ...notebook.data, remote: true };
+    newNotebook.topics.push(makeTopic("Home", id));
+
+    await expect(db.notebooks.merge(newNotebook)).resolves.not.toThrow();
+
+    expect(notebook.topics.has("Home")).toBe(true);
+    expect(notebook.topics.has("General")).toBe(true);
+    expect(notebook.topics.has("hello")).toBe(true);
+  }));
+
+test("merge notebook with topics removed", () =>
+  notebookTest().then(async ({ db, id }) => {
+    let notebook = db.notebooks.notebook(id);
+
+    const newNotebook = { ...notebook.data, remote: true };
+    newNotebook.topics.splice(1, 1); // remove hello topic
+    newNotebook.topics.push(makeTopic("Home", id));
+
+    await expect(db.notebooks.merge(newNotebook)).resolves.not.toThrow();
+
+    expect(notebook.topics.has("Home")).toBe(true);
+    expect(notebook.topics.has("General")).toBe(true);
+    expect(notebook.topics.has("hello")).toBe(false);
+  }));
+
+test("merge notebook with topic edited", () =>
+  notebookTest().then(async ({ db, id }) => {
+    let notebook = db.notebooks.notebook(id);
+
+    const newNotebook = { ...notebook.data, remote: true };
+    newNotebook.topics[1].title = "hello (edited)";
+
+    await expect(db.notebooks.merge(newNotebook)).resolves.not.toThrow();
+
+    expect(notebook.topics.has("hello (edited)")).toBe(true);
+    expect(notebook.topics.has("hello")).toBe(false);
+  }));
+
+test("merge notebook when local notebook is also edited", () =>
+  notebookTest().then(async ({ db, id }) => {
+    let notebook = db.notebooks.notebook(id);
+
+    const newNotebook = { ...notebook.data, remote: true };
+    newNotebook.topics[1].title = "hello (edited)";
+
+    await delay(500);
+
+    await notebook.topics.add({
+      ...notebook.topics.all[1],
+      title: "hello (edited too)",
+    });
+
+    await expect(db.notebooks.merge(newNotebook)).resolves.not.toThrow();
+
+    expect(notebook.topics.has("hello (edited too)")).toBe(true);
+    expect(notebook.topics.has("hello (edited)")).toBe(false);
+    expect(notebook.topics.has("hello")).toBe(false);
+  }));
+
+test("merge notebook with topic removed that is edited in the local notebook", () =>
+  notebookTest().then(async ({ db, id }) => {
+    let notebook = db.notebooks.notebook(id);
+
+    const newNotebook = { ...notebook.data, remote: true };
+    newNotebook.topics.splice(1, 1); // remove hello topic
+
+    await delay(500);
+
+    await notebook.topics.add({
+      ...notebook.topics.all[1],
+      title: "hello (i exist)",
+    });
+
+    await expect(db.notebooks.merge(newNotebook)).resolves.not.toThrow();
+
+    expect(notebook.topics.has("hello (i exist)")).toBe(true);
+    expect(notebook.topics.has("hello")).toBe(false);
+  }));
+
+function delay(ms) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
diff --git a/packages/core/api/sync/merger.js b/packages/core/api/sync/merger.js
index 0ab77e2d6..3d3dcb3d0 100644
--- a/packages/core/api/sync/merger.js
+++ b/packages/core/api/sync/merger.js
@@ -106,7 +106,7 @@ class Merger {
     await this._mergeArray(
       notebooks,
       (id) => this._db.notebooks.notebook(id),
-      (item) => this._db.notebooks.add(item)
+      (item) => this._db.notebooks.merge(item)
     );
 
     await this._mergeArrayWithConflicts(
diff --git a/packages/core/collections/notebooks.js b/packages/core/collections/notebooks.js
index 4aaa5cbb0..a5100784c 100644
--- a/packages/core/collections/notebooks.js
+++ b/packages/core/collections/notebooks.js
@@ -6,12 +6,46 @@ import { CHECK_IDS, sendCheckUserStatusEvent } from "../common";
 import { qclone } from "qclone";
 
 export default class Notebooks extends Collection {
+  async merge(remoteNotebook) {
+    const id = remoteNotebook.id || getId();
+    let localNotebook = this._collection.getItem(id);
+
+    if (localNotebook && localNotebook.topics?.length) {
+      // merge new and old topics
+
+      // We need to handle 3 cases:
+      for (let oldTopic of localNotebook.topics) {
+        const newTopicIndex = remoteNotebook.topics.findIndex(
+          (t) => t.id === oldTopic.id
+        );
+        const newTopic = remoteNotebook.topics[newTopicIndex];
+
+        // CASE 1: if topic exists in old notebook but not in new notebook, it's deleted.
+        // However, if the dateEdited of topic in the old notebook is > the dateEdited of newNotebook
+        // it was newly added or edited so add it to the new notebook.
+        if (!newTopic && oldTopic.dateEdited > remoteNotebook.dateEdited) {
+          remoteNotebook.topics.push(oldTopic);
+        }
+
+        // CASE 2: if topic exists in new notebook but not in old notebook, it's new.
+        // This case will be automatically handled as the new notebook is our source of truth.
+
+        // CASE 3: if topic exists in both notebooks:
+        //      if oldTopic.dateEdited > newTopic.dateEdited: we keep oldTopic.
+        if (newTopic && oldTopic.dateEdited > newTopic.dateEdited) {
+          remoteNotebook.topics[newTopicIndex] = oldTopic;
+        }
+      }
+    }
+    return await this._collection.addItem(remoteNotebook);
+  }
+
   async add(notebookArg) {
     if (!notebookArg) throw new Error("Notebook cannot be undefined or null.");
-
-    if (notebookArg.remote) {
-      return await this._collection.addItem(notebookArg);
-    }
+    if (notebookArg.remote)
+      throw new Error(
+        "Please use db.notebooks.merge to merge remote notebooks"
+      );
 
     //TODO reliably and efficiently check for duplicates.
     const id = notebookArg.id || getId();
diff --git a/packages/core/collections/topics.js b/packages/core/collections/topics.js
index e8eeaf4a0..defd03d93 100644
--- a/packages/core/collections/topics.js
+++ b/packages/core/collections/topics.js
@@ -111,7 +111,8 @@ export default class Topics {
   }
 }
 
-function makeTopic(topic, notebookId) {
+// we export this for testing.
+export function makeTopic(topic, notebookId) {
   if (typeof topic !== "string") return topic;
   return {
     type: "topic",