If you're interested in the Sokolsky/Orangutan/Polish (1.b4) and like books with encyclopedia-style coverage, the new Russell Enterprises offering
1.b4: Theory & Practice of the Sokolsky Opening by FM Jerzy Konikowski and Marek Soszynski is the thing for you. I recall many reviews of the Lapshun and Conticello book on the same opening receiving serious criticism for their comparatively thin coverage; this cannot be said of the present volume. In fact, I think there is too much information here.
Sometimes we think the point of an opening book is to acquire information. That's true, but only up to a point. A good database will give us loads of information, but if the games aren't annotated and we don't know how to weight the information that's there, it presents the opposite problem. Now instead of lacking information, we're drowning in it. Thefore, the main reasons to buy an opening book are to get rid of the excess information we get in a database and to learn what ideas, move orders and plans are important. It's not to know or have access to every single idea in every single variation of an opening or line. As this work is much more like a print database than a typical opening book, the reader will have to sift through a colossal amount of material to develop a repertoire, and the strategic advice is comparatively sparse.
Bottom line: Konikowski and Sosynski have put in an incredible amount of effort compiling the material and including their own analysis. This includes a great deal of material from Sokolsky himself, which is quite valuable to English readers lacking access to the founding father's works. That's to K & S's credit. Unfortunately, the product is still in too raw a form for all but devoted fans of 1.b4. If you're a serious 1.b4 player, then it's a must-buy based on its thoroughness. If you're looking for an intro, however, it's a lot less useful.
The book is available
here.