The theory for frames and bases has developed rapidly in recent years because of its role as a mathematical tool in signal and image processing. This is the first comprehensive book to focus on the general properties and interplay of frames and Riesz bases, emphasizing their mathematical aspects. Rich in exercises, applications, and open problems, the work is aimed at graduate students and researchers in pure and applied mathematics, math physics, and engineering. Minimal prerequisites also make the book accessible to professionals working in digital signal processing who wish to understand the theory behind many modern signal processing tools.