If you love programming and consider it an art or craft, as I do, this book is for you. You will learn why Lisp is a simply amazing and beyond any other programming language. Definitely not for beginners, I strongly recommend this book for intermediate to advanced Lisp programmers, and for other advanced programming professionals who want to get a taste of the language.
Let Over Lambda contains brilliant coverage of macros, as other reviewers have pointed out, but it is not just about macros. Hoyte presents the context of macros as they exist within the full range of Lisp capabilities. He compares Lisp to C, in terms of the detailed mechanics behind data structure and memory access, something that is not easily found elsewhere - showing how macros and functions can be used to construct C-like pointers, for example. In this way the reader will get a more complete understanding of the language and how it works and demonstrates that there is simply no other language with the power of Lisp.
Expect to spend some time with this book, and expect to return to it for deeper consideration again and again. The first chapters go rather quickly, but later material should be carefully considered step by step, not only for thought-provoking concepts and paradigms, but also the associated Lisp implementations.
Hoyte should be applauded for informing us of the beautiful constructs he illustrates. We all see further by standing on the shoulders of giants, and with this book Hoyte has also offered his shoulders to us lesser mortals.
If you want to master Lisp macros this is the book for you. However, make sure you know the basics of Common Lisp as this book does not aim to give the reader any basic language information. The book is very clear for understanding the motivation to use macros and steadily builds examples, with good insights into tricks of the trade and performance concerns.
A very stimulating book to take the reader to the next level of Lisp mastery!