The Vanishing Thieves is the title of a Hardy Boys Digest novel, written by Franklin W. Dixon

Franklin W. Dixon

Franklin W. Dixon is the pen name used by a variety of different authors who wrote The Hardy Boys novels for the Stratemeyer Syndicate...

. Sometimes it goes by the number of 66 in the series, a continuation of the original novels, and sometimes as the 8th, as it is the 8th published by Simon & Schuster

Simon & Schuster

Simon & Schuster, Inc., a division of CBS Corporation, is a publisher founded in New York City in 1924 by Richard L. Simon and M. Lincoln Schuster. It is one of the four largest English-language publishers, alongside Random House, Penguin and HarperCollins...

 after Grosset & Dunlap

Grosset & Dunlap

Grosset & Dunlap is a United States book publisher founded in 1898.The company was purchased by G. P. Putnam's Sons in 1982 and today is part of the British publishing conglomerate, Pearson PLC through its American subsidiary Penguin Group....

 lost rights to publish new Hardy Boys books in 1979.

Plot summary

Chet Morton's cousin, Vern, is on his way to California to find a rare and valuable coin mysteriously missing from his uncle's bank vault. When he stops in Bayport, his brand-new car is stolen. The Hardys take on a double mystery-and double danger as they head for the West Coast to investigate this sinister mystery.