Tons of books - digitized mostly from the early 1900's and earlier free to download and print if you desire.
I have probably downloaded 10 books on local mining history today - nearly any topic though.
Save it to your computer for later reading so you will have something to do when at your mother-in-laws visiting..... [waiting]... provided you don't forget your laptop... [ouch]
http://books.google.com/books (http://books.google.com/books)
Books still in copyright are not available for download and have limited or no search, but to me, the best technology is the old technology. Easier to recreate at home.
Looks like Google reached a court settlement with Authors and Publishers and there will soon be more access to copyrighted books - maybe online purchase to read, etc.