"The Policeman's Daughter" by Wil McCarthy

A fascinating tale about a future where duplicating people is as easy as stepping into a 'fax' machine and you are expected to keep 'archive' copies of yourself for backup. Into this steps a private investigator who get a weird case. An old friend asks him to protect his life from a murderer: the old friend's earlier self. When confronted, the earlier self wants to settle the matter in court but only if he is defended by the investigator's earlier self too. Expect multiple personality mayhem to take place.

• Read excerpt from Analog SF, June 2005 (http://www.analogsf.com/0506/policemans.shtml)