books.google.com - This book is intended to complement my Elements oi Algebra, and it is similarly motivated by the problem of solving polynomial equations. However, it is independent of the algebra book, and probably easier. In Elements oi Algebra we sought solution by radicals, and this led to the concepts of fields...http://books.google.com/books/about/Elements_of_Number_Theory.html?id=LiAlZO2ntKAC&utm_source=gb-gplus-shareElements of Number Theory