This book contains everything a player would need for his adventures on the Wilderlands: new (including amazons, altanian barbarians, avalonians, different human cultures, etc.), three new classes (the alchemist, the amazon warrior and the witch), new skills, feats, rules, spells, and of course, description of the Wilderlands, the City State of the Invincible Overlord, and the gods. Interestingly for player's guide, even monsters are included. The races, classes aren't well balanced, but this is part of the old-school feel of the product.
While I recommend this for everyone, who plays a Wilderlands campaign with D&D3.5 rules, I simply can't ignore the low quality of the pdf. No bookmarks, no index, no table of contents, and the maps seem to be poorly scanned, with low resolution. Alas, since it's out of print, this is the only choice we have...