I bought this item in a fit of Old School nostalgia, and I am very pleased to say it hit the spot!
Roughly half this book details out a campaign world that - while I may read for inspiration and enjoyment - i will probably never use. It is well thought out and covers the necessary bases for a game world.
But the rest contains so many cool and useful bits that I want to use in a game. In addition to fleshing out the basic Sword and Wizardry class with sub-classes such as Berserkers and Rune Casters and Clerics of Thor, this book introduces rules for Rogues, non-Adventurer classes, new races (and new takes on old races) and a complete and playable skill system that doesn't require a ton of rules, charts or fiddly bits. Round things out with some new monsters, new magic items, and rules for Ritual Magic.
There are a few typos and lay out issues, but I feel such things are quibbles in the face of the sheer amount of cool stuff this book hands to you.
[5 of 5 Stars!]