See/Saw - Paperback

America in the year 2030: Storefront businesses serve "donors" who sell episodes from their memories ("memplants") to anyone willing to pay for them. Memplanting began as a tool for psychotherapy, but inevitably became devoted to the buying and selling of sex memories ("sexmems"). Robert Morgan, a divorced and recently terminated assistant professor, buys a sexmem that happens to include the memory of an accidentally observed murder. Now the killer is looking for Morgan, to silence the only witness.