I love old nonfiction, though. There's a certain time period, post-WWII to about 1970 I think, that manufactured books that now, with age, have a great smell. The best used bookstores smell this way.
The design of the covers from this time period is good, too.

At my old clerk job, one of my duties was taking the deselected (nice use of librarian-speak, eh?) children's nonfiction out of our catalog. I also got first dibs on any discarded books I wanted. This is why my copies of the first 4 Harry Potters have broken spines, multiple repairs, and look like library property.
Mostly, though, I like out of date nonfiction. I have a book about Communism from the 1960s, written for children. I published a zine at one point of pictures of scientists from 1950s science books for kids.*
One of the sections adult services was weeding was all the old space exploration books. I wanted to adopt them all, even though I suspect I already own at least one of the titles we were getting rid of. Artist's renderings of space travel, the future, and the surface of other planets are something I never get tired of.
Plus, sometimes old books are just fun to mock.

I don't know if you can tell, but every single one of those pictures is identical. A more accurate title would be, 24 Table Saw Projects, All of Which Look Exactly Alike.

I like to think this entire book is dedicated to making sure you don't buy a ring this ugly.

Killer bison!!! I know you can't tell, but it's eyes are totally red, too. And it may or may not be foaming at the mouth. I also like this one because it looks like the awesome caveman hunting/TRex double-sided mural they used to have at the Carnegie Museum (behind the TRex). Its historical inaccuracies always irritated my dad, but I miss it.
It's a short jump from mocking books to mocking authors. For example, if you had written this book:

Wouldn't you choose a bigger horn-thing to hold in your picture?

And here, finally, is the best one. I giggled like a schoolgirl for about twenty minutes over this, plus showed my coworkers and made them giggle. I am, after all, so good at my job because of my stunted maturity.

*I still have copies, if anyone wants one. Darren, I'll trade you one for a nudie pen.