Production well logging techniques provide information necessary for efficient and economical well production. The various techniques are summarized and grouped into the three phases of well production. Temperature logs, radioactive tracer logs and velocity logs are used to obtain cement tops and indications of cement channeling in well completion work. In well repair work encroaching gas and water may be located by various neutron logging techniques, the temperature log, the flowing fluid density log, the gamma-gamma log and the conductivity log. Well evaluation work, including fracture location, injectivity profiles and productivity profiles can be facilitated by use of radioactive tracer logs and the flowmeter log. Field examples are presented to demonstrate usage of the many logging techniques. Interesting applications of the flowing neutron log are shown including multiple gas-oil contact location, gas "coning" and dual completion logging operations. Location of water entry by the flowing fluid density log and the conductivity log are illustrated. The "Humble" flowmeter is briefly discussed. Future development trends in the field of production well logging conclude the paper.