I made a mistake and sent the wrong person my book. How do I contact the original requestor.

Hi Anne,

You should see a PM message next to the active transaction on your "My Account" tab.

This is actually so common that there is a huge page in the Help Center about it. (It is a pop up page so I cannot link to it.)

I sent the wrong book to another member (including: I mixed up two book requests)

Yes, I've done it once, also. It's kind of inevitable. Usually people are very nice and understanding.

Once I got a book meant for another member, and she got mine.  All we did was mail each other the correct book, so it was easy in our case.  (We each just got a credit from original sender in lieu of postage to remail book which I thought was fair).