Why doesn't Nintendo sue this guy for using the name of a popular game character for his book title?

THe entire lawsuit is without merit, as though the concept of and focus of story are the same, the actual plot and intent of the two works are separate. One is quite adamant about the society changing effects of Genetic memory devices and their connection to religion, while the other is more interested in events in the past being relived on a personal level: the device is not explored as tech breakthrough, but as a medium for the game's story. In other words, in AC genetic memory is an important element of the story, but the story is not explicitly about genetic memory. If a book was made about a new technology that let everyone teleport and the trouble it causes, they couldn't sue Jumper, for example.Secondly, "damages" cannot be completely proven to be incurred if a casual check of "Link" shows that it recieved little fanfare or profit before AC was released, and yet AC made a profit on it's own merit with a majority of it's consumer base (gamers) being unaware of the novel's existence. The lawsuit has to prove that AC prevented purchases of Link, or caused confusion of brand: "I meant to buy that novel about genetic memory and assassins, but instead I found this crummy video game! In a bookstore even, what is this I don't even...", because if in court it can be proven that the average consumer can tell the difference between the two works (and not just because they are in different mediums) then Link failed to profit simply because it was not as successful as AC, not because AC successful.And finally it is not illegal for works to have simlar aspects, or concepts, as long as those concepts are named differently and not 1:1. If Link was about a Miles Desmond who is forcefully abducted from his bar so an evil corporation could use his memories to uncover an ancient war between two equally ancient conspiracies, then there could be cause for idea theft..
I could totally make a book about someone using a device to explore genetic memory during the crusades, and even heavily feature Ḥashshāshīn, but as long as characters, story arc, and descriptory content were entirely original, it would be fine, especialy if I made no attempt to look or sound like Assassin's Creed.
If AC gets hit with a lawsuit and is forced to pay, then that might be trouble for things like S.T.A.L.K.E.R., which I don't know if it received permission from the writers of Roadside Picnic or the movie Stalker.

there's more........

Yeah... so the description I read on the book is probably nowhere close to what the full story is, but from the sounds of it, Assassin's Creed is only similar in a couple ideas. The book explores the identity of the "soul" through this machine that lets you RECALL ancestral memories in specific moments. Assassin's creed has a machine that lets you LIVE as your ancestor in a fairly strict sense, and as far as we know you can live as the ancestor whenever and the game only has us go through specifics, but it's definitely not for finding the meaning of a "soul". And unless the book has a guild/faction of assassins somewhere his "discusses assassinations" claim can go suck a big one. So, really, the ideas are similar, but in my mind nowhere close enough to bring up a copyright infringement.

Screw him, I want AC3.