The lonley planet on Chicago gives the keen traveller some really good guidance. Having lived in the "windy city" for a while I found all the information in the lp correct and up-to-date.
I especially liked the architectural walk, where the lp takes you to some of the intriguing buildings and gives you some interesting background on the specific architecture.
Also, all the information on the art and cultural venues in the city are precise. Of course, the lp can't know it all, hence, some of the jazzy highlights where not mentioned, but you can't have it all!
I'd buy it again