Keith Melton is the holder of the largest collection of privately held espionage artifacts with thousands of items. The collection is not open to the public. Discovery Times Square has a temporary exhibit of his more important pieces from his collection on display beginning May 18, 2012.
The official CIA manual of trickery and deception According to WorldCat, "The manuals reprinted in this work represent the only known complete copy of Mulholland's instructions for CIA officers on the magician's art of deception and secret communications written to counter Soviet mind-control and interrogation techniques." 
He has also created many more books with Jim Wiese.