The work for the fiscal year of 1958 on Basic Fatigue Research has been directed towards obtaining methods for designing fatigue resistant structures. Two such methods have been obtained 1 the use of rivets driven through the edge of splice doublers, and 2 the use of thin auxiliary doublers to permit using extra rivets away from the high stress area in the main splice doubler. Test data show that a substantially lighter structure could be had for the same fatigue life by using either of the two methods, or a lifetime of up to twenty times that of an equivalent weight structure of conventional design. Thin doublers are being used in the Models 880 and 600. Edge driven rivets have been approved for operators of commercial airlines in repairs or as fatigue inhibitors of airplanes now in service. Convair has a patent pending on edge driven rivets. Miscellaneous data are also presented on fatigue behavior and on photoelastic analysis of stress distribution in simulated and built up structures.