Part of a Record/Comic package (SLP-188) offered by Golden Records. The album cover for the record has at the top "GOLDEN RECORD MARVEL AGE COMIC SPECTACULARS" and at the bottom a Marvel logo and "A MARVEL COMIC GROUP BOOK AND RECORD".
There is no indicia, no date (not even a copyright statement), and the only reference to Marvel is the MC on the cover. According to the ad on the back cover, this is part of a set of four Marvel books and two DC ones. One of the DC ones (Superman) has a 1966 copyright date, so that should place this book also in 1966. These sets are listed as available from Golden Records, 250 West 57th Street, New York, NY 10019. In that ad this book and record set was offered for 2.49 USD.