Porsche loves to make radical concept cars that often become real production cars, looking extremely similar to their concept counterparts (see Taycan). But have you ever wondered about the other concepts that don’t see the light of day?

Enter Porsche Unseen, a 328-page book filled with insights into the company’s design process, and visions that the German brand has toyed with for 15 different cars. Never-before-seen design studies and prototypes are found in this book, including these three:

Porsche 919 Street. “What would happen if Porsche turned the 919 Hybrid LMP1 race car into a street-legal car?” This is what you’ll get. Many changes were made to the outer shell to make it road-legal, but underneath, the same carbon monocoque shell and drivetrain can be found—just detuned to make it tame enough to be driven by mortals.

Porsche Vision Spyder. This design study draws inspiration from the 1954 Porsche 550 Spyder. A spartan interior, a low windshield, radiator grilles over the mid-mounted engine, racing graphics, and an “ultra-modern roll bar” make up this concept. Fans of James Dean will certainly notice the “Little Rebel” license plate.

Porsche Vision Renndienst. Here’s the design team’s interpretation of a futuristic space shuttle, an example of the Porsche design DNA flexing its muscles by showing off how well it works on vehicle types Porsche has never done before. A spunky-looking electric minivan, anyone?

There are more interesting cars that can be found inside this book, which is now available with the ISBN number 978-3-667-11980-3. No word if our very own Fully Booked has it in stock, but this is one thing that we’d love to see underneath our Christmas tree.