Amazon.com
Like the preceding episode "What Are Little Girls Made Of?", "Dagger of the Mind" is another mad-doctor drama. This time, Kirk delivers supplies to a penal colony on Tantalus V, where he meets the renowned Dr. Tristan Adams. Adams has been working on the development of a neural neutralizer to control and manipulate dangerous patients. When Kirk threatens to expose him as a dangerous megalomaniac, Adams uses the technology on the unfortunate captain. This tense piece set in a madhouse atmosphere makes for a riveting episode, with a few unhinged performances adding to the fun.
--Tom Keogh
From the Back Cover
While delivering supplies to a penal colony, an inmate escapes to the
Enterprise and demands sanctuary.
TREK TRIVIA
James Gregory (Dr. Tristan Adams) was later seen as General Ursus in Beneath The Planet Of The Apes and as Inspector Frank Lunger on TV's Barney Miller. Morgan Woodward (Dr. Simon Van Gelder) returned as Captain Ronald Tracy for the second-season episode "The Omega Glory."
"Dagger Of The Mind" was the first show to display Spock's Vulcan Mind Meld abilities. Note that Kirk records his Captain's Log into a tricorder instead of his command chair!