The book that finally allows The Strange to come into its own.
The Strange was supposed to be a campaign of infinite recursions for players to explore and instead all of the earlier books (with the exception of the bestiary) seemed to focus almost exclusively on Ardeyn (and to a lesser degree Ruk).
The Core book covered Ardeyn, Ruk and The Strange in exhausting detail, but only provided minimal coverage of other recursions. 6 recursions had 2-3 pages worth of coverage and another 11 had minimal 1/6 page overviews. In contrast Worlds Numberless and Strange gives 5-8 page write ups to 17 new recursions and1/4-1/2 page overviews of another 48 recursions. With this book the campaign setting begins to finally fulfill some of its original promise.
The new recursions are generally pretty good. The best are those that take familiar elements and add a twist. One such example is my favorite recursion an Arthurian world that has been invaded by a nanovirus from another recursion. Arthur's dead, Merlin's disappeared, Lancelot is a drunk, Percival, Galahad and most of the rest of the round table are nanovirus monsters and Mordred is now the hero. Another example is the Eleventh Reich a recursion where the Nazi's triumphed and now spend there time trying studying and trying to control holy artifacts like in the Indiana Jones films with about as much success.
I can not recommend this book highly enough, definitely the best book in The Strange product line so far