"Open source" essentially means a content source that can be edited by anyone willing to contribute. Think wikipedia. So I would not be surprised if this is essentially a collection of wikipedia articles (which have been contributed by "experts" from all over the world) that have been given an edit then fed into a print-on-demand service like Lightning Source. So essentially you're paying for a bunch of wikipedia-like articles (if not wikipedia articles outright).
I noticed a similar book now available on Amazon entitled Indiana Jones and the Staff of Kings. I'd hoped it was a novelization of the videogame, but the product description reads as "High Quality Content by WIKIPEDIA articles! Indiana Jones and the Staff of Kings is a historical fantasy video game published by LucasArts for the Wii, Nintendo DS, PlayStation 2, and PlayStation Portable. The game is the third in the series of original 3D Indiana Jones games, preceded by Indiana Jones and the Emperor's Tomb, and Indiana Jones and the Infernal Machine.he plot centers around Indy's search for the Staff of Moses." So, kind of lame.
Personally, I would avoid this stuff.