viii, 238pp. Dark purple cloth-covered boards, blind embossed emblem on front, gilt titles on spine, several black and white diagrams. 8vo. Boards lightly soiled. Spine lightly sun-faded and soiled. Spine ends and corners lightly rubbed and rounded. Text block edges tanning. Front endpapers very lightly soiled. Light tanning around page margins. Volume quite loose. With chapters on the higher frequencies, magnetron oscillation, the klystron, etc.