diff --git a/libs/shared-state-books/src/lib/books.reducer.ts b/libs/shared-state-books/src/lib/books.reducer.ts
index 89efeef..5d6270f 100644
--- a/libs/shared-state-books/src/lib/books.reducer.ts
+++ b/libs/shared-state-books/src/lib/books.reducer.ts
@@ -60,3 +60,16 @@ export const reducer = createReducer(
     };
   })
 );
+
+export const selectAll = (state: State) => state.collection;
+export const selectActiveBookId = (state: State) => state.activeBookId;
+export const selectActiveBook = createSelector(
+  selectAll,
+  selectActiveBookId,
+  (books, activeBookId) =>
+    books.find((book) => book.id === activeBookId) || null
+);
+export const selectEarningsTotals = createSelector(
+  selectAll,
+  calculateBooksGrossEarnings
+);