Practical Common Lisp is an introductory book on the programming language Common Lisp by Peter Seibel.
[1] It features a fairly complete introduction to the language interspersed with practical example chapters, which show developing various pieces of software[2][3] such as a unit testing framework, a library for parsing ID3 tags, a spam filter, and a SHOUTcast server.
[4] At the Jolt Product Excellence and Productivity Awards in 2006, it won a Productivity Award in the technical book category.
[5] The full text is available online.
[6] In a 2006 Google TechTalk, Seibel presented the book's main points in the context of linguistic relativity (the Sapir–Whorf hypothesis).