OK "modern" might be a misnomer, all concepts are 20+ yo here, but... async with promises (like in basic concurrency without execution parallelism, just io p), channels, then actors, stm maybe. Most books seem to have a chapter on threads and stop there. I know CL has libs for all these and the libs have docs, but was hoping for some "big picture" summary of what's worth using and learning from the entire ecosystem and when etc.

>but was hoping for some "big picture" summary of what's worth using and learning from the entire ecosystem and when etc.

Google "Common Lisp Cookbook", it has a chapter that will give you something of a "big picture".

If you find a good actors library, let me know. I've been using CL for 20 years and have not found a satisfying one.

[edit]

CL is in a slightly uncomfortable position here; scheme has first-class continuations, which makes implementing actors and async the sort of thing that could be an undergrad assignment, most other languages have a single source of truth (either with a language committee like C++ or with a one-true-implementation like Python).

cl-async is perfectly good for async.