Palimpsest is a civilization-creating game, a la Microscope, where you build a world layer by historical layer, creating a rich, complicated, sometimes paved-over history.
The PDF is 15 pages, with a strong cover and fun, well-composed layout. The majority of the art is stock photography...but phrasing it that way kind of undersells it, as the photos break through the book's whitespace, join together like building materials, peel off of the page like bark, and in general make for an extremely engaging backdrop for the game's text.
To play Palimpsest, you define some loose facts about a civilization, pick an angle to that civilization that interests you, and either establish a piece of that civilization's history, create something that will outlast the civilization, discover something from a previous civilization, or look at the civilization in a new light.
Over time, each civilization falls and a new one picks up, but as you bury the civilizations in turn you create a rich bedrock for your setting.
The game flow is easy to follow, and there's a handy reference sheet at the end. There's also some safety mechanics at the beginning in case you accidentally veer into territory that messes you up. Notably, every civilization in palimpsest has an expiry date on it, but they don't have to all end in fire. Some can simply give way to their successors, allowing your setting to be as peaceful or as chaotic as you wish.
I think Palimpsest is a cool utility if you *really* want to flesh out a whole game world, or if you want to play a very big-picture world-building game.
If you like settings with a lot of archaeology and prior cultures, you should definitely pick this up, but it also feels like it'd be fun as a one-shot or a way to get your creativity in gear before starting a big campaign.