Designers are obsessed with books because it is the most fundamental object in the field. Everything else is more or less ephemeral, ads are thrown away the next day, posters end up in the bin, flyers barely make it to the recipient's hand. Magazines and newspapers get thrown once read. Books however stay in shelves or on coffee tables. In other words objects in themselves.
Graphic design is all about making this for others to see (perhaps design in general). Designers are vain like that, even if there is a lot more to design than just making pretty things. Anyone trying to convince you of anything else are lying about how giddy they got the first time they saw something they made in print. Because of the limited lifespan of the other things designers make, the book becomes extra special due to it's much longer lifespan.
That said, PieBie makes a good point over, this question is a bit too open ended for this forum.