These free books would be good if you into compiler design.

As for data structures, go to this page and read the reviews of different books. That should give you an idea of how good a book is.

About compilers they proposed us this book:
Programming Language Pragmatics second edition
http://www.amazon.com/Programming-La...7434167&sr=1-1

And for data structures :
Kurt Melhorn: Data Structures and Algorithms 1: Sorting and Searching, Springer Verlag

They seem like really good books!!!

For compiler design : Compilers-Principles-Techniques-Tools-2nd
This is a very nice book.. it is available as an ebook for free too.....

For datastructures : Datastructures and program design by robert kruse would be nice for beginners....

To go stil deeper into algorithms and all, Introdution to algorithms by cormen would be nice........

I would go for "Data Structures and algorithm analysis" by Mark Allen Weiss.