The Disappearing Floor, The Hardy Boys Mystery Stories #19 in the series. Author: Franklin W. Dixon. 218 printed pages pages. Hardcover book, no dust jacket. Publisher: Grosset & Dunlap, copyright 1940, printed circa 1957 in the U.S.A.

The 1957 printing has brown multi-scene endpapers.

Synopsis:  Frank and Joe Hardy get caught up in a strange mystery when some jewel thieves come to their town. The boys soon discover that the case involves a strange mansion filled with baffling scientific inventions, including rooms with vanishing floors and eerie optical illusions. As they try to find the thieves, they also have to deal with some tough guys who won't let them uncover their secrets.

The brothers follow hints that lead them through caves, into labs with strange machines, and into dangerous spots where the floors seem to vanish underfoot. With the help of their father, Fenton Hardy, and their friends, the boys unravel the gang’s schemes, expose the criminals, and recover the stolen jewels

Condition: The book is in very good plus condition with no noticeable problems. (see photos).