I don't buy into stuff like this personally.
I can kinda understand it for a Mass Effect as that series has a fricking encyclopedia built into it but for Gears of War and Halo? Screams of money grabbing, hold as much story/lore back as you can, flesh it out and make em buy the book to know just WTF is going on in the game.
Halo is especially bad for this.
No problem with gaming novels in theory, just seems some abuse them to ring more money out of ya.
Most Wanted of 2014: InFAMOUS Second Son, Mario Kart 8, Evolve, Destiny, The Order 1886
+ Titanfall, Watch_Dogs, Bayonetta 2, Smash Bros, Murusaki Baby, Hotline Miami 2, Lords of The Fallen, Hyper Light Drifter, Alien Isolation.