Structures: lightweight records, a step before classes
Error and condition handling
Scripting. Parsing command line arguments, building self-contained executables.
cl-torrents, app and (extensive) tutorial: web scraping and building executables
Continuous Integration and delivery on Gitlab CI, testing locally with Docker
Installing libraries, dependencies management
Lisp software
Why do we have to wait one month for Quicklisp updates ?
How to do Functional Programming in Common Lisp ?