Other features that have piqued my interest (besides the already mentioned, and vitally important, macros) are: - conditoins and restarts - CLOS - reader macro

Other features that have piqued my interest (besides the already mentioned, and vitally important, macros) are: - conditoins and restarts - CLOS - reader macros (which are distinctly different from normal macros). If you're talking about other Lisps (besides CL), like Scheme, it's worth looking at define-syntax and syntax-rules and how they deal with some of the intricacies of creating macros with define-macro.