The complete Historia Augusta has been up on LacusCurtius for seven years now, and in all that time the reader going to its orientation page will have read that there was an introduction by the Loeb editor, and a little section on the manuscripts — but that I hadn’t put them up, and would do so in the fullness of time.
Of course I quickly forgot about the missing items; yesterday must have been the fullness of time, and I had occasion to discover them again. They’re now up: Introduction and Manuscripts.
David Magie’s explanation of just how people consider the Historia Augusta a pack of lies is reasonably thorough and clear. But the more useful and interesting explanation is in fact on Livius; though less complete and technically detailed, that’s still the one I recommend.