We got this note from Jim Rossman at Commonwealth Associates:

Northwest Refuse accepts books. They were very accommodating when I showed up with a pickup truck full. They helped me load the boxes of books onto a pallet set atop a fork lift truck.

I also contacted Recycle Ann Arbor. They have two methods of recycling books. Books to be recycled into pulp product are to be taken to their South Industrial Rd. site (734-662-6288; Mon-Sat 9-5; Sunday 10-2). Books (no encyclopedias) suitable for re-use may be dropped off at their 2950 E. Ellsworth Rd. facility (Mon-Sat 9-5). I was told that there is a drop-off charge of $3 at the E. Ellsworth Rd. facility. I believe there is a charge levied at the S. Industrial Dr. station, as well.

Thanks for the tip, Jim!