Get it right, get it working, and then get it fast. And have the computer do most of the work for you. That's the premise of Algebra-Driven Design [ADD]. ADD is a fundamentally different approach to the software design process. By finding the essential algebra behind our programs, we become able reason about correctness with mathematical precision. It encourages algebraic manipulation of programs to find optimizations, and helps uncovers the inherent structure in our domains. Best of all, the resulting code is guaranteed to be free of abstraction leaks, and in many cases, actually writes itself. If that sounds like the sort of software you'd like to write, this is the book for you. Sandy guides you through the process of Algebra-Driven Design, from thinking about laws to deriving programs. You'll learn how to playfully explore your domain, find observations, exploit symmetry, and automatically generate enormous test-suites. The journey is complete with real-world case studies, and reference material for mastering the tricky bits.