“The Art of Problem Solving, Introduction to Number Theory , 2nd Edition is a comprehensive textbook focusing on number theory for high school students. Published by Aops Incorporated in 2013, this paperback book contains 480 pages and is written in English. Authored by Mathew Crawford, this intermediate-level textbook provides a detailed introduction to number theory concepts, making it a valuable resource for students looking to strengthen their math skills.” Set contains 2 books. Problems book and Solutions book.