Palladium Books is a company that has been publishing Roleplaying Game Books since 1981, and has published game books in most major genres of RPG, including high fantasy, contemporary horror, superhero and modern warfare. Their most important game is currently Rifts, a genre-spanning game of magic and high technology set in a post-apocalyptic earth.
The original book put out by Palladium was the Palladium RPG, which was a fairly conventional high fantasy Role Playing Game, which didn't seem to differ from Dungeons & Dragons much either in setting or in game mechanics. Palladium probably became famous because they had the good fortune to license the Teenage Mutant Ninja Turtles (in their original, underground, black & white form) before they became famous. Then, in the early 1990s, they released Rifts, a world that tied together magic, high technology, and every other possible aspect of fantasy or science fiction in a world that was post-apocalyptic and vaguely cyberpunk. Rifts has become their major property, with somewhere around two dozen expansion books published, detailing every aspect of the post-apocalyptic mad house the world has become.
Palladium books are, in my opinion, notable for two things: a truly creative mixing of technology and fantasy into an involved world of politics; and a lack of editing, planning, and sense of scope. The books do have a fairly engaging description of different characters, and a "realistic" approach to describing the political structure and intrigues of the places they describe. For example, when the books describe the political and sociological structure of the lost continent of Atlantis, it is, as far as such a thing can go, pretty believable. On the other hand, the books go into exhaustive detail about minutiae of weaponry and geography, and seem to lack editing, in that they often seem to be a connection of random "cool ideas" rather than a well-planned story description.
An extreme example of this (and somewhat unfair, since it was an early entry, but it is still emblematic of the problem) is a book entitled The Palladium RPG Book II: The Old Ones. The Old Ones are super-powerful cthonic entities in the mythology of Palladium, and this adventure module describes a descent into their secret lair. At least, the one-third of the book does. The first two-thirds of the book different towns you can visit, in exhaustive detail. Do you need to know where the bakery or basket maker is in two dozen different fictional towns? Well, that is what most of that first two-thirds of the book is about. And this is what many Palladium Books are like: interesting ideas crowded out with page upon page of badly designed cruft.