THE AVENGING MIND.
I'm sure most people reading this are familiar with this oft-reprinted story. A man who is disturbed by mysterious dreams goes to Doctor Strange's Greenwich Village home to enlist the help of the fabled mystic. After a brief astral trip to Asia to consult his teacher, the Ancient One, Strange enters the man's dream, where he finds out the reason for his guilt, but also encounters his long-time foe Nightmare. With his physical body and astral form in danger, Strange calls on the Ancient One to help, which he does with the use of the mysterious eye contained in Doctor Strange's amulet.
This is a classic story, remarkable for how clearly it lays out the vision for the series in only five pages. While Doctor Strange's outfit and face would undergo some tweaking in the issues ahead, the main elements are all here. We also get the Greenwich home (with a few early hints of the design elements which would define it), the Ancient One and his mountainside home, the astral form and a great villain in Nightmare. And the hands, of course, we get some of the Ditko mystic hands.
As near as I can figure, this story (via its 1978 Pocket Books reprint) is probably the first place I laid eyes on Ditko's artwork, some 30 years ago. It's even fresher and more alive now than it was then.
Ditko plots, pencils and inks the 5-page story.