BISCHOF, George P.: A Brief Course in Strength of Materials, Prentice-Hall, Inc., paperback, 93 pages, index, 1947, Surprisingly, this is a well written simple approach explaining the basics, is (was?) a Brooklyn Technical High School textbook.
MORLEY, Arthur: Strength of Material, 3rd. Edition, Longmans, Green and Co., hardcover, 248 diagrams, 497 pages, index. A well written mix between a Strength of Materials textbook and Advanced Strength of Materials. Covers many subject generally not found in later textbooks. He also wrote Theory of Structures, Longmans, Green and Co., hardcover, 390 diagrams, 611 pages, index. His textbooks may be freely downloaded from the Internet.
MEGSON, T. H. G.: Aircraft Structures for Engineering Students, Edward Arnold, hardcover, index, 1972. This is an English textbook covering basic stress-structural analyses of aircraft structures not covered in other similar textbooks.
MURPHY, Glenn: Advanced Mechanics of Materials, McGrew-Hill, Inc., hardcover, 307 pages, 1946.