Lots of good reviews/suggestions here. Let me add mine:
Bidding On Target, George Rosenkranz and Alan Truscott
Intermediate to Advanced, B+
Some chapter headings: "Problems of Second Hand", "Problems of Third Hand", "Constructive Bidding", "Slam Bidding".
This is a "theory" book - but with many example hands. Great discussions of Notrump bidding and preemptive bidding, lots of good stuff on tightening up partnership understandings.
Bid to Win, Play for Pleasure, George Rosenkranz
Godfrey's Bridge Challenge, George Rosenkranz and Philip Alder
Godfrey's Stairway to the Stars, George Rosenkranz and Philip Alder
Godfrey's Angel's, George Rosenkranz and Philip Alder
These four books describe the modern Romex system. The first is a pretty large book, with an awful lot of stuff in it. The last three are written in a conversational style, and take the reader through Godfrey's teaching his wife Meche and her regular partner Mayté the basics of the Romex system. Very good reading, and I think Romex deserves wider recognition than it's had.
Intermediate to Advanced, B+