Resources for the Common Lisp language:
One of the best resources to learn Common Lisp nowadays. It's more recent than the alternatives, and is focused on getting things done™ in Common Lisp, as opposed to being a reference on the language.
This book is also recommended by E. Weitz in the Common Lisp Recipes book below.
One of the best Common Lisp books around. Edmund Weitz is one of the most notable Common Lisp hackers: he's written drakma, cl-pccre, hunchentoot, cl-who, cl-interpol, among other libraries that are the community standard in Common Lisp.
It's similar in spirit to the "Common Lisp Cookbook", but this is much more in-depth and is of a higher quality in general compared to the Cookbook. For example, in Chapter 16 there's a very enlightening discussion on the image-based development workflow – which is the natural way to work in Lisp, but that is not familiar to most programmers nowadays.
Chapters 16, 11, 22 are very interesting.
List of Common Lisp users, authors, and other people involved in the free and open-source Common Lisp community.
Recipes on how to do all sorts of common tasks with Common Lisp.
A curated list of Common Lisp libraries.