Grosset & Dunlap, New York, 1962.  9120.  Hard cover, 176 pages.  Illustrated matte finished boards with some edge, corner and spine end wear, light soil and a bit of wrinkling on rear board, small scrape on front board.  Binding sound; green top stain with a few small spots, light soil at lower fore-edge and a bit of moisture rippling to some lower page edges.  Illustrated end papers, black & white frontis and interior drawings with illustrations by Charles Brey.  ‘”Someone has stolen your invention!”  Bud Barclay tells his pal Tom Swift Jr.  And when a scientist in France publicly tests a helium-extraction machine, it seems Bud is right.  The machine explodes, precisely as Tom predicted any model made from his own unperfected plans would do.  But the explosion is only the beginning of one of the strangest mysteries in the young scientist-inventor’s career.’ (from initial page)