This volume does what is sets out to do: explore ideas to expand AD&D based on hints from Gary Gygax prior to his ill-fated devorce settlement, when his huberous got the best of him and he gave up controlling interest in TSR in favor of the D&D series and film rights.
The best part of this book is the new class options, the first 24 pages. The most interesting of these is the mountebank, a Cudgle the Cleaver meets Han Solo type, and the Jester, basically turning any character into a Kender. These classes expand roleplaying possibilities with concepts like verbal patter, also key to the version of the bard presented here. There are strict spell casting classes too, most notably the mystic, a Taoist type. I'm not crazy about the secondary skills system because I don't like a lot of number crunching, but it is very Gygax. It's very much like the one he wrote for Castles & Crusades, using an experience point purchasing system. The combat system gives various options for adding complexity to combat. My favorite is the percentage chance of causing friendly fire in missile combat, which I don't remember from AD&D. There's also stuff here for dealing with various environments, at least as usefull, probably more so, than the post Gygax Dungeoneer's and Wilderness Survival Guides. I apprieciate the expanded waterborne combat, as a lot of OSR material tends to neglect it. The new monsters are Judeo-Christian extra planer-- choirs of angels and various demons. BRW Games strategically released this the same week as the Commemorative Edition AD&D books. I want the hard cover of A Curious Volume for the mountebank class alone. The best part of the book is that the options are modular. Take or leave what you want.
[4 of 5 Stars!]