Unlike the error-riddled DC ENCYCLOPEDIA, this compendium — published by the same company — is an excellent reference book that summarizes all the various universes and continuities that DC Comics has featured, from Crises, Convergences, New 52s and Rebirths, right up to the current Infinite Frontier of all possibilities. As Grant Morrison states in the foreword, the book sets out to be an indispensable guide to the "current state of play, mapping and cataloguing eight decades of worldbuilding into one convenient gazeteer".
    There are feature pages on the Legion, L.E.G.I.O.N., Legion-connected races and allies, the Subs, and other Legion-related characters. Interestingly, the section on the Legion uses one of the Perez spreads from LEGION OF THREE WORLDS without word balloons … revealing the likes of Kid Quantum, Nightwind, Atmos and Dawnstar in her alternate costume. This clean version has been seen on social media in the past, and on this very site, but this is the first time it's appeared in print.