This is a collaborative project that aims to provide for Common Lisp something similar to the Perl Cookbook published by O'Reilly. More details about what it is and what it isn't can be found in this thread from comp.lang.lisp. The credit for finally giving birth to the project probably goes to "dj_special_ed" who posted this message to comp.lang.lisp. If you want to contribute to the CL Cookbook,
