One book to consider is:
It isn't specifically about the Hanseatic League, but I think it provides very useful context for them, and their rise and fall. Since the Baltic was such an important trade route (and is still important), a history of the Baltic must devote attention to trade, and thus the Hanseatic League and their rise and fall. The Hansa-relevant section is about 60 pages, or about 20% of the main text. Possibly unfortunately, many of the references are to books and papers in languages other than English.