Offered is the book entitled: The Principles Underlying Radio Communication. This is an early US Army Signal Corps book marked:  Radio Pamphlet No. 40, December 10, 1918.  Signal Corps, US Army.  The book is clean and in good condition with some wear at the corners and edges. The first page is stamped by the Office Coast Artillery Corps.  Washington Govt. Printing Office. 350 Pages, with many illustrations and diagrams as well as (3) Appendix. Prepared by the Bureau of Standards under the direction of the Office of the Chief Signal Officer of the Army, Training Section. Written by DR. J H Dellinger, Dr. F W Grover, Prof. C M Smith, Prof G F Wittig, Dr. A D Cole, Dr. L P Wheeler and Prof. H M Royal.  Pick up the book for your own collection.  These books don't come up for bidding too often. From the radioman's estate collection-from a smoke and pet-free home. Mouse all over the many photo images to zoom in.  NO RESERVE!! Thanks for looking.