[armitron]

A lot of libraries that don't have separate documentation in the form of HTML/PDF/README.. are actually well-documented at source level in the form of docstrings.

Since Common Lisp is an interactive programming language and is meant to be used interactively (think Smalltalk, not Python) it is common practice to (interactively) load a library in a Common Lisp image and explore it (interactively). One can see what symbols are exported from packages, what these symbols are used for and (interactively) retrieve their documentation. All of this takes place within the editing environment (ideally Emacs) in a rapid feedback loop (again think Smalltalk, not Python) that feels seamless and tremendously empowering.