diff --git a/cli/cmd/publish.go b/cli/cmd/publish.go
index e522438..dfde7ce 100644
--- a/cli/cmd/publish.go
+++ b/cli/cmd/publish.go
@@ -69,21 +69,36 @@ func publishBookRecords(session atproto.Session, books []store.Book, storePath s
 
 	var failed []string
 
-	// TODO:
 	// call ListBookRecords and build an index:
-	// existing, err := atproto.ListBookRecords(session)
-	//
-	// then, build a map[string]book of olWorkId and isbn13 values already on the pds
+	existingRecords, err := atproto.ListBookRecords(session)
+	if err != nil {
+		return fmt.Errorf("listing book records: %w", err)
+	}
+
+	// then, build a map[string]record of olWorkId and isbn13 values already on the pds
+	index := make(map[string]atproto.RepoRecord)
 
+	for _, record := range existingRecords {
+		if record.Value.OLWorkID != "" {
+			index[record.Value.OLWorkID] = record
+		} else if record.Value.ISBN13 != "" {
+			index[record.Value.ISBN13] = record
+		}
+	}
 	// **Loop over unpublished books** — for each, build a `BookRecord` from the store book (`OLWorkID`, `ISBN` → `ISBN13`, `DateAdded` → `CreatedAt`)
 	for i, book := range books {
 		if book.ATURI != "" {
 			continue
 		}
 
-		// TODO: add a guard for book already indexed
-		// if existingIndex[book.OLWorkID] || existingIndex[book.ISBN] {continue}
-	}
+		// guard for book already indexed
+		_, ok := index[book.OLWorkID]
+		if !ok {
+			_, ok = index[book.ISBN]
+		}
+		if ok {
+			continue
+		}
 
 		record := atproto.BookRecord{
 			OLWorkID:  book.OLWorkID,
diff --git a/cli/internal/atproto/records.go b/cli/internal/atproto/records.go
index 6b2e429..d8cdaf7 100644
--- a/cli/internal/atproto/records.go
+++ b/cli/internal/atproto/records.go
@@ -5,22 +5,9 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"net/url"
 )
 
-// TODO:
-//	type ListRecordsResponse struct {
-//	    Records []struct {
-//	        URI    string      `json:"uri"`
-//	        CID    string      `json:"cid"`
-//	        Value  BookRecord  `json:"value"`
-//	    } `json:"records"`
-//	    Cursor string `json:"cursor"`
-//	}
-//
-// TODO:
-// function to fetch existing book records from PDS, paginated via cursor
-// func ListBookRecords(session Session) (ListRecordsResponse, error)
-
 type BookRecord struct {
 	OLWorkID  string `json:"olWorkId,omitempty"`
 	ISBN13    string `json:"isbn13,omitempty"`
@@ -50,6 +37,75 @@ type CreateRecordResponse struct {
 	CID string `json:"cid"`
 }
 
+type ListRecordsResponse struct {
+	Records []RepoRecord `json:"records"`
+	Cursor  string       `json:"cursor"`
+}
+
+type RepoRecord struct {
+	URI   string     `json:"uri"`
+	CID   string     `json:"cid"`
+	Value BookRecord `json:"value"`
+}
+
+// fetch existing book records from PDS, paginated via cursor
+func ListBookRecords(session Session) ([]RepoRecord, error) {
+
+	cursor := ""
+	var allRecords []RepoRecord
+
+	for {
+		params := url.Values{}
+		params.Set("repo", session.DID)
+		params.Set("collection", "com.hectorsector.book.book")
+		params.Set("limit", "100")
+
+		if cursor != "" {
+			params.Set("cursor", cursor)
+		}
+
+		// GET from com.atproto.repo.listRecords, pass in params:
+		url := session.PDSHost + "/xrpc/com.atproto.repo.listRecords?" + params.Encode()
+		req, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			return nil, fmt.Errorf("creating request: %w", err)
+		}
+		req.Header.Set("Authorization", "Bearer "+session.AccessJwt)
+
+		// Call with no cursor, get records and maybe a cursor
+		response, err := http.DefaultClient.Do(req)
+		if err != nil {
+			return nil, fmt.Errorf("listing records for pds: %w", err)
+		}
+
+		if response.StatusCode == 401 {
+			return nil, fmt.Errorf("Invalid creds when calling PDS <Status code: %s>", response.Status)
+		}
+
+		if response.StatusCode != 200 {
+			return nil, fmt.Errorf("Got non-200 response from calling PDS <Status code: %s>", response.Status)
+		}
+
+		var listRecordResponse ListRecordsResponse
+		err = json.NewDecoder(response.Body).Decode(&listRecordResponse)
+		if err != nil {
+			return nil, fmt.Errorf("decoding response from pds: %w", err)
+		}
+		response.Body.Close()
+
+		allRecords = append(allRecords, listRecordResponse.Records...)
+
+		// while cursor:
+		// 	call again and the cursor
+		if listRecordResponse.Cursor == "" {
+			break
+		}
+		cursor = listRecordResponse.Cursor
+	}
+
+	return allRecords, nil
+}
+
 func CreateRecord(session Session, collection string, record any) (CreateRecordResponse, error) {
 	reqBody, err := json.Marshal(CreateRecordRequest{
 		Repo:       session.DID,