In response to a previous post of mine, Phil Wolff has also been thinking about the use of RFIDs in library books:

"My paranoid fantasy...

So we stick RFID tags in every book, starting at the publisher; ISBN Inside(TM). I check out of the library and go about my life.

I'm walking down the street and get scanned. The police are scanning the street for people carrying the Anarchist's Cookbook. Cult members accost me because I'm carrying Judaica. Merchants tailor signage. Republicans stone me. Beggars ask for more money.

These are books inside my knapsack, my pocket, my car; hidden from view.  

If the books I'm carrying are hooked up to my mobile phone profile, you might get just-in-time book salons and lunch meetings. Lovely Smart Mobs stuff.

But privacy doesn't stop at the library doors.

Just something to consider." [a klog apart]

He's got a point, and we definitely do need to take these kinds of issues into consideration. However, even if we don't put RFIDs in books, the publishers will. Who do you trust more to implement them in a way that protects your privacy?  ;-)