The object proposed in this study is to consider both the activities and the importance of the Pathfinder Force, Royal Air Force, in the Second World War. Their story has a much earlier beginning than 15 August 1942 when the founder squadrons gathered on various R.A.F. stations in the vicinity of the cathedral city of Ely in Cambridgeshire. Some form of target finding and marking became inevitable from the moment it was acknowledged that the preparations that had been made for war during the 1930s were less than adequate. The arguments that ensued pior to August 1942 were much less concerned with the need, than with the form, such a force should take. Unfortunately, while the administrative in-fighting surged back and forth, R.A.F. aircrews went to war not only insufficiently trained but also poorly equipped. Necessity and duty drove these men to attempt to combat weather conditions and enemy defensive measures in aircraft, that all too frequently, were unfitted for the roles they were expected to fulfil. To their credit they pressed on despite the hazards of weather, the fury of enemy defences and the deficiencies of their aircraft and equipment. Regardless of the forces of nature and man ranged against them, the crews of Bomber Command and the Pathfinder Force pressed on. It is therefore fitting that 'Press on Regardless' became the unofficial motto of the Pathfinder Force. It would also provide a singularly apt epitaph for the 3,727 men of the Pathfinder Force who were killed on operations. This work has been written in tribute to all who served in the Pathfinder Force but particularly to those who failed to return.