This is an Oversized 10 x 14 inch Treasury sized comic, which were very popular and common in the 1970's.
The pages are twice the size of the original comic books, but the height of each page is slightly less in comparison. This means that many of the comic book panels have been cropped at the bottom, and many of the characters feet, which were visible in the original version, are cut off.
This issue was published in two versions, One by Marvel Comics, the other by Whitman Publishing. The Whitman version has the "W" logo replacing the Comics code logo, but the rest of the comic is the same.
The cover for this issue was also used for The Marvel Comics Illustrated Version of Star Wars novel sized edition.