Handbook of advanced algorithms I am looking for resources (preferably a handbook) on advanced topics in algorithms (topics beyond what is covered in algorithms textbooks like CLRS and DPV). 

The type of material that can be used for teaching a topics in algorithms course like 
Erik Demaine and David Karger's Advanced Algorithms course.

Resources that would give an overview of the field (like a handbook) are preferable, 
but more focused resources like Vijay Vazirani's "Approximation Algorithms" book are also fine.
The Design of Approximation Algorithms by Williamson &amp; Shmoys (http://www.designofapproxalgs.com/) is a great book for many approximation methods such as greedy algorithms, semidefinite programming, etc. Also, it covers some topics within complexity that are closely related to approximation algorithms (inapproximability, Unique Games-based hardness of MAX-CUT).