Question: Which book is more a beginner to learn to program in c++ (or GML) and more fun: "Game Maker 8 Cookbook" (available for pre-order), or "The Game Maker's Companion" ?

Answer: 
I created a game in Game Maker long ago, and was frustrated with the lack of control over many of the game elements. They try to take the programming out of game making. So I'm afraid you won't find Game Maker to be much help if you're trying to learn C++, or really programming in general.
I would recommend going with [Beginning C++ Through Game Programming, Third Edition](http://rads.stackoverflow.com/amzn/click/1435457420) if you want to achieve your intended goal.
I don't think either of them look all that great, and certainly they don't appear to teach C++ at all (focusing instead entirely on Game Maker and GML, it's internal language). 

"Cookbook" style books tend to be more focused around isolated, individual techniques rather than providing a unifying educational "narrative," so I would shy away from the "Game Maker 8 Cookbook" entirely if that's what you are looking for.

Additionally, "The Game Maker's Companion" is a follow-up, so perhaps the first book in the series, [The Game Maker's Apprentice](http://rads.stackoverflow.com/amzn/click/1590596153) is a better choice overall.