About Tom Swift, Jr. - Boys’ series of  33 well-written, imaginative science adventure books published  from 1954 through 1971. These followed the earlier 1910-4140-volume Tom Swift series, but are NOT revisions/condensations of the earlier series. They are entirely new plots with new characters, but feature some of the family and friends of the earlier series.  So the admired and groundbreaking new inventions of the Jr. series are from a much later era, inspired by the space flight advances then in the works, and in the news of the day. 

#27 in the series.

Grosset and Dunlap. Copyright 1966. Rear cover lists to the next volume, Mystery Comet, also first published in 1966.  This may be a second printing.  

Excellent, clean picture cover book with slight spine slant.  Black/white space lab endpapers. No writing/markings, no tracking, minimal corner bumping.

In this one, Tom and Bud need to build an aquarium and stock it with deep-sea creatures in a race against time, and for that mission Tom invents a "mole mobile" geotron, a burrowing craft which bores through earth as under the ocean floor.
 

TS27