The Ninth International Workshop on Persistent Object Systems (POS 9) took place at the SAS Radisson Hotel in Lillehammer, Norway, from 6th to 8th September 2000. Previous workshops in the series have been held in Scotland (1 and 2), Australia (3), the USA (4), Italy (5), France (6), and the USA (7 and 8). In keeping with those workshops, POS 9 was short but intensive, fitting 28 papers and panel sessions, a boat 1 excursion, and some memorable meals into two and a half days. The participants' concentration was no doubt helped by the Northern European weather that prevailed for most of the...