Let over Lambda–50 Years of Lisp

Let Over Lambda is Doug Hoyte’s advanced tutorial on Common Lisp, focused on macros: code that generates code. It argues that macros are Lisp’s defining strength because they let programmers create abstractions and language features unavailable in ordinary programming, improving productivity while making code more efficient and secure. Rather than offering a conventional manual of general-purpose techniques, the book aims to show how Lisp can expand the boundaries of programming. It begins with fundamentals and moves toward increasingly sophisticated macro techniques, while presenting the material as both practical and an invitation to think differently about programming.

Published in 2008 to mark 50 years since Lisp’s invention, the book runs more than 376 pages. Its later chapters explore anaphoric macros and culminate in “pandoric-eval,” a particularly ambitious macro. The site provides the table of contents, online text, code, references, reviews, errata, and clarifications, and notes that a Japanese translation is available. In a 2026 update, Hoyte says that programming practice and his own views have evolved, but he still considers the book a useful tutorial and explanation of what makes Lisp distinctive. He has made the complete book free to read online in HTML and PDF.