The Elder Scrolls Online has been available since April, but it's only just now making its Steam debut.
Bethesda announced today that both the Standard and Imperial Editions of the game will be available through the digital storefront later today. If you recall, the Imperial Edition, which retails for $99.99, includes all sorts of bonuses and goodies like a 12" Molag Bal statue, a 224-page illustrated guide, and a physical map of Tamriel.
Looking ahead, the next major update for ESO is due to arrive in August, with Xbox One and PS4 versions still on the horizon. ESO was originally due out for release on next-gen consoles in June 2014, but a delay was announced in May. Bethesda maintains that they've been progressing steadily, but we still don't have a release date for those versions yet. Perhaps we'll find out more during the QuakeCon panel set for tomorrow.