I saw the Rick Steves Berlin book at a local bookstore. This is the first edition, and it was published in September 2017. A few months ago I had to purchase the Germany book with 700 pages just to get the information about Berlin since RS did not have the Berlin book for distribution at that time; this is for a trip that begins in less than one week. The Berlin section took up about 140 pages. The Berlin book has about 450 pages. There are several more walks (e.g., Cold War sites) in the new book plus additional information (eg, a page about the Stasi). This is a great volume if visiting Berlin is in your future. Do not buy the Germany book unless you plan to see other parts of that country.
RS has said that these days more tourists visit Berlin than visit Rome. It's about time that Berlin got its own book.
Geor(ge) - a native son of Berlin