Aircraft, with their rapidly increasing use of plywoods bonded with synthetic-resin adhesives, have made imperative a study of the behavior of both wood and adhesives under vibrating loads. It is desirable for aircraft engineers to know if the wood or the adhesive is likely to fail under repeated stress, what allowable stresses may be employed for various loading conditions, and what the endurance limit may be. Should the bond show a tendency to fail, it is desirable to know if certain adhesives behave better than others. In this paper are contained some of the results so far obtained in a continuing program of research into the behavior of plywood and laminated wood of both normal and high density. Results on only normal-density plywood and laminated wood, bonded with thermosetting phenol-formaldehyde resin and with cold-setting urea-formaldehyde resin, are presented.