In the days before comic book sized trade paperback compilation books (commonly mistaken as “graphic novels” which is something entirely different) comic companies published digest sized books which were comprised of previously published stories.
This is an issue of The Best of DC No. 12 which features compilation of Superman stories and is collectively titled, Superman in Time and Space. This 100 page digest book from 1981 contains six stories: Bus-Ride to Nowhere, The Sun of Superman, Starry-Eyed Siren of Space, Planet of Angels, Superman, Youʻre Dead… Dead… Dead, and Secret of the Space Souvenirs.
The cover was created specifically for this digest book by Ross Andru and Dick Giordano.