How to Solve it By Computer by Dromey though not exactly an algorithms book takes the approach of re-discovering the process by which many data-structures and algorithms were arrived at over the years. This allows us to understand the flow of thought behind the code and some of the forces at work.
Related: This book follows in the foot-steps of another great book: How to Solve It by G. Polya which talks about how great mathematicians go about the problem-solving process.
