Yeah but you should read this trilogy, it is written by Greg Bear who is a very good sci-fi author. And before you say that it doesn't matter, don't, because this trilogy was commissioned by 343 themselves so its content are very important to the Reclaimer trilogy.
For example, the other trilogy been written by Karen Traviss already mentioned the Spartan IV program and if you are the type that can connect the dots, it was obvious that the SIVs are going to show up in Halo 4, even the human ship shown in the concept art trailer was mentioned in the book, and frankly I have an idea about how the humans got to the shield world, again, based on these new books, so, no they are important though not necessary to follow the story that is going to be in the game.
For someone like me who is only interested in the singleplayer campaign and the overall fiction of the universe, it means a lot more to me. It is important to note that 343 are trying to create a more cohesive universe and are making sure that there is no conflict and retcons between the expanded universe and the games, but the expanded universe will never be necessary to follow the game but they will be rewarding to those who care that sort of thing. (danmmit, didn't mean to type so much)