Sorry, no threading for Lisp. Not sure you may even need threading perse.
For example:
I did threading in the last UNIX app I wrote; my app read from one file and wrote to another. I choose to implement threading because it was fun(er) and I wanted/needed atomic reading/writing. So, in other words, my app needed to read/write the file(s) in sequential chunks, and I wanted to make sure that wasn't interrupted. To do that I created a simple synchro method (a function to manage threads in case a process was blocked) to read a chunk of text and pass that along to other function(s) to parse/do something.
My threading monitor function just monitors an array of file descriptors and if an operation causes a thread to block, my function then schedules another runnable thread. In a single threaded operation if a process blocks, the entire operation needs to block (wait). The process I was preforming took nanoseconds on my 10 year old laptop so in reality my monitoring function was only creating two threads but like I said above, I was playing around too.
After I finish my process my synchro function just joins all the threads and closes up shop.
So, in crude terms, my app will "write or wait to write". It is a sort of guarantee for making sure data isn't corrupted. This isn't a "have one thread calculate this" and "another thread do that" type of thing because in the case of a long/involved calculation your other threads would have to block until information becomes available (the calc is preformed) so threading would gain you nothing (and you don't need atomic operations).