Tom Swift and the Electronic Hydrolung

Price from Tuck. First printing date "1961" identified on the copyright page. Issued with no dust jacket. Publisher's blue denim cloth used in Series from 1-17 is replaced with full color pictorial cloth that wraps into the spine with the series number "18" appearing in black letters in a white diamond below illustrated portrait of TS, Jr. Spine cloth on later printings are in either solid blue or yellow cloth. $1 price appears in white along with "No.18" in a small black box with a single white rule in the upper right corner of the front cover. The series' illustrated endpapers are retained, however the half title and backlist on the verso are discontinued from this point forward. The series backlist appears in black letters over a blue cloth field on the back cover ending with No.18.