Which is the best book to start learning algorithms?
I have read books by Mark Allen, Udi Manber partly and CLRS completely. I think CLRS is probably the best book.
Introduction to Algorithms by CLRS is a pretty comprehensive book and starts from scratch. There is almost no pre-requisite for reading that book expect some basic high school math. The pseudo codes are much better and the math behind each and every data structure is explained is best way possible. The exercises at the end of each chapter are of sufficient difficult level. However if you are slow learner the amount of data in CLRS can be a little overwhelming.
Overall CLRS is the best book for a beginner. Check out my related answer here - What does Ashish Kedia think about the book 'Introduction To Algorithms by CLRS'? How he has studied the book?