Jean-Pierre Serre 
Abelian l-Adic Representations and Elliptic Curves [PDF ebook] 

This classic book contains an introduction to systems of l-adic representations, a topic of great importance in number theory and algebraic geometry, as reflected by the spectacular recent developments on the Taniyama-Weil conjecture and Fermat’s Last Theorem. The initial chapters are devoted to the Abelian case (complex multiplication), where one