This may not be the answer you're looking for, but I think you might get the highest ratio of information-to-time by just trying it out. Second-hand opinions ar

This may not be the answer you're looking for, but I think you might get the highest ratio of information-to-time by just trying it out. Second-hand opinions are hard. Practical Common Lisp is the best intro, and two chapters (maybe 40 min) in you'll know if it's worth going further.