Ten minutes after takeoff from Munich, while passing FL180, the crew smelled something abnormal. A few moments later, increasingly dense smoke became noticeable in the area of the overhead panel. The flightcrew declared an emergency and decided to return to Munich. The “Electrical Smoke in Cockpit” checklist did not provide guidance on how to identify the origin of the smoke or how to isolate the source of the fire. Because the smoke was rapidly thickening, the crew was unable to read and complete the checklist. After declaring an emergency, the aircraft received radar guidance by approach control to land at Munich. The flightcrew reported that crew coordination became difficult and that the captain’s flight instruments began to fail sporadically. The flightcrew further reported that visibility in the cockpit became extremely limited. The investigation found that the flightcrew did not take timely or appropriate actions to eliminate smoke from the cockpit. Initially, the flightcrew did not depressurize the cabin which prevented the opening of the cockpit window. After switching the cabin pressurization system to “manual,” the flightcrew reported that they were too preoccupied with flying and preparing to land the airplane to open the window. The investigation of the incident found indications of a smoldering fire in the overhead electrical panel. Electrical wires, terminal blocks, and the emergency power switch, Part Number (P/N) 103-200, were charred or burnt. The direction of the propagation of the smoke and fire indicated that the fire had originated in the area of the emergency power switch.