I got this a couple of years ago and was quite pleased. Apart from the odd English grammar (the author is not a native speaker, so I can forgive that), it is a good starting point for a low-level adventuring party or a drop-in location in a sandbox campaign. Since it does not clarify just what the nature of the Medusa truly is, I decided I would use it in a sci-fi campaign rather than fantasy. My Medusa was a woman with access to technology that emulated the mythical creature's powers. This is worth grabbing whatever genre you decide to use it in. It certainly convinced me to try the rest of the materials released by 0One.