This book has been developed from notes and blue prints prepared by the writer and used in his classes at the University of Illinois. Certain additional material has been added, a part of which has been briefly presented in a number of articles contributed by the writer to the technical press. The notes referred to above were modeled after a set prepared by Dr. N. C. Ricker, several years before, to whom the writer is greatly indebted.<br><br>Many additional problems might have been added and the discussion greatly extended. This is especially true of Chapters IV and VII to X inclusive. However, it has been thought best to keep the book to smaller proportions, and the writer believes that a thorough mastery of the constructions and solutions here presented will give the student an excellent grasp of the subject.<br><br>The object has been to deal with the analysis of stresses rather than with design or the computation of loads. Nevertheless it has seemed desirable to give some attention to the determination of loads, and Chapter IX has been devoted almost exclusively to design. Material and ideas have, of course, been drawn from many sources.<br><br>The writer is especially indebted to Prof. C. R. Clark for assistance in connection with the early part of the work and to Prof. L. H. Provine for encouragement and constructive criticism.