The Fourth Edition of AHistory amends and vastly expands (by about 40%) the work of Third Edition, continuing to incorporate the whole of Doctor Who into a single timeline. All told, this Fourth Edition takes about 2000 (!!!!!) full-length Doctor Who stories and dates them in a single chronology --- starting with the Universe's origins and working its way forward to the end of time.
Specifically, this Fourth Edition covers all Doctor Who TV episodes through the end of the twelfth Doctor era starring Peter Capaldi (Twice Upon a Time); all New Series Adventures up through Diamond Dogs; the Big Finish audio range up through Static (#233); all Torchwood, The Sarah Jane Adventures, K9 and Class episodes, novels and comics; the Titan, IDW and Doctor Who Magazine comics; and a cornucopia of other Doctor Who spin-off series (Jago & Litefoot, Counter-Measures and more).
Volume 2 (of 3) of Ahistory Fourth Edition encompasses the Present Day, UNIT, Modern Day (through 2017) and Gallifrey sections of the Doctor Who universe.
All told, the three volumes of Ahistory Fourth Edition contain more than a million words of hardcore geeky analysis on the world's longest-running Sci-Fi series.