A longer version of Lampson's 1983 paper, this ebook suggests the goals you might have for your system — Simple, Timely, Efficient, Adaptable, Dependable, Yummy (STEADY) — and techniques for achieving them — Approximate, Incremental, Divide & Conquer (AID). It also gives some principles for system design that are more than just hints, and many examples of how to apply the ideas.