2018 International Residential Code (IRC Code Book): ISBN 9781609837372

You will find that this textbook breaks down difficult topics into manageable chunks.

International Residential Code Paperback IRC 2018

You will find that this study guide improves your recall during open-book tests.

IRC 2021 International Residential Code 2021 with Fast Tabs

A nice touch in this textbook is the list of suggested readings at the end.