B737-300
Distraction; Workload; Human-Machine Interface
Aircraft Equipment Problem Critical
Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Inflight Shutdown; Flight Crew FLC complied w / Automation / Advisory; General Declared Emergency
Aircraft
Climbing through 22;000 feet the aircraft suddenly yawed left with a faint thud noise. The thrust stopped abruptly. My first thought was the Yaw Damper kicked off or was malfunctioning.  Then when we realized the engine quit. I thought maybe it flamed out because of no perceived damage. The Captain immediately took control. I was inclined to run the Engine Failure/Shutdown Checklist leading to a relight as there was no overheat; no fire indication; no vibration; and N1 and N2 were turning.  We also had a deferred APU which complicated things just a bit. The Captain elected to run Engine Fire Severe Damage/Separation.  I facilitated with memory items (very fresh in my head having just got out of training) and the running of the QRH leading into the Single Engine Landing Checklist; while handling the radios with ATC and coordinating our return to ZZZ after we determined it was our closest suitable airport. Landed uneventfully.
A B737-300 engine failed during climb so after running the QRH; an emergency was declared and the flight returned to the departure airport for an uneventful landing.