I'll be frank: my book does not touch this topic in the slightest, and this is an open question. Common Lisp does not have any asynchronous features built in an

I'll be frank: my book does not touch this topic in the slightest, and this is an open question. Common Lisp does not have any asynchronous features built in and, as I've said in some earlier comment, the condition system is fully synchronous. This topic is still waiting to be explored, either with an extension of Common Lisp or a completely different language that permits asynchronous programming with an adaptation of the condition system to this programming paradigm.