Saw someone mention this book on Facebook and went out and found an ARC of it:
Silverberg, Robert. Time and Time Again. Three Rooms Press, 2018. Advanced Reading Copy of the trade paperback original first edition, a Fine copy, new and unread. All Silverberg’s time travel stories in one place. Bought for $9.99 off eBay.
There was evidently a signed “preview” edition sold at this year’s Worldcon (which I no longer attend), which I may have track down at some point, but this ARC precedes the preview edition.