This stunning coffee-table book of B&W photographs of Chicago's Capone era has some great shots.  I think my favorite is the one of the Birger Gang, a cheerful group of bootleggers posed on and around a car and holding a wide variety of firearms, including pistols, rifles, and Tommy guns, though there are many others of equal interest.  Gangsters, both alive and dead (the St. Valentine's Day Massacre is of course represented), cops, molls (Hymie Weiss' widow looks pretty happy about things), Feds, old buildings, sporting events.  All of them are captured in fine and sometimes surprising detail.  There's just enough text by John Russick, from Chicago's History Museum, to let you know what each picture's about, but for the most part the photos speak for themselves.  This kind of book is wonderful for browsing, and it's the kind of thing you'll find yourself returning to often.