Good books to learn social choice theory I wanted to learn Social Choice Theory and have fine mathematical background. I have read about it as a part of advanced microeconomics (Jehle and Rene)- Arrow's Impossibility Theorem etc. and got intrigued by it.

What are some good books to read to know more about Social Choice Theory and in particular, the mathematics of voting systems?
Start with:


A primer in Social Choice Theory, by Wulf Gaertner.


If you want more, have a look at:


Welfare Economics and Social Choice Theory by Allan Feldman and Roberto Serrano


To dig deeper:


Handbook of Social Choice and Welfare
By A. Sen, Kotaro Suzumura 
Handbook of Social Choice and Voting by Jac C. Heckelman, Nicholas R. Miller
Handbook of Computational Social Choice by Ariel D. Procaccia, Jérôme Lang, Felix Brandt, Vincent Conitzer, Ulle Endriss
The Handbook of Rational and Social Choice by Clemens Puppe, Prasanta Pattanaik, Paul Anand


For good or bad reasons, there are also entire books dedicated to the specific method of "approval voting" (which tend to discuss other methods as well as a way to enable comparisons):


Approval Voting by Brams and Fishburn 
To dig deeper: Handbook of Approval Voting, by M. Remzi Sanver, Jean-François Laslier


To branch out into the neighboring disciplines of mechanism and market design:


Multiagent Systems, Algorithmic, Game-Theoretic, and Logical Foundations, by Yoav Shoham and Kevin Leyton-Brown
Essentials of Game Theory, A Concise, Multidisciplinary Introduction, by Yoav Shoham and Kevin Leyton-Brown (some redundancies with previous reference) 
Auction Theory, by Krishna 
Market Design, Auction and Matching, by Haeringer