In the 1960s I spent hours in the basement running my film projector, playing all of my Castle Films and Republic small reel movies. Adventures of Captain Marvel was my favorite mini-movie. I had to splice the celluloid together now and then with scotch tape, but I did get a lot of use out of it. Just think, all 12 chapters condensed into a few minutes running time. Now that's editing.
Ronald Stephenson informed me this booklet is one of several published by Jack Mathis in the late 60s or early 70s. Mathis wrote Valley of the Cliffhangers and Republic Confidential. His Valley of the Cliffhangers Supplement gave the chapter by chapter synopsis and cliffhanger photos for all 66 Republic serials.