From the introduction:
If you’re a fan of good old-fashioned Marvel Mayhem, have we got a treat for you. Contained in this book are the stats for hundreds of Marvel and DC characters for use in the classic Marvel Super Heroes Role-Playing Game.
The material in this mighty tome was originally compiled by Gabitch, based on materials from the web. Gabitch’s book compiled many rule changes and errata from other sources, which I have subsequently done away with. Simplicity being the rule, it just wasn’t necessary to reprint every Dragon magazine article and every house rule that’s been posted on the web.
All I have done is condensed the prior work into something easy to use for the Judge or Player who already has the requisite rulebooks. Hopefully, I was successful.
This item includes illustrations that probably are copyright infringing. Too, it includes extensive material derived from various copyrighted sources integrated with user-generated contest. Generally, these materials are not properly attributed.