From: FAA-H-8083-25B "Pilot's Handbook of Aeronautical Knowledge"
Page 14-2, Nontowered Airport
"A nontowered airport does not have an operating control tower. Two-way radio communications are not required, although it is a good operating practice for pilots to transmit their intentions on the specified frequency for the benefit of other traffic in the area. "
46. Inbound to an airport with no tower or UNICOM in operation, a pilot should self-announce on MULTICOM frequency