Spearhead From Space is the third DVD in the Doctor Who – The Doctors Revisited Volume 1 collection. This is a very enjoyable episode and, appropriately, the first story featuring Jon Pertwee. This means fans learn the origins of Pertwee's Doctor affection for frilly shirts, capes, and jalopies. Like the others in this set, the story is available in both widescreen feature format with an introduction by Steven Moffat and the original fullscreen 4 episodes. I recommend watching Moffat's introduction and then watching this Doctor Who in the original fullscreen.
Story wise, number 51 Spearhead From Space is pretty good. A bunch of meteors land on earth. UNIT and its newest member, scientist Liz Shaw, investigate. Lethbridge-Stewart is a bit nonplussed at the arrival of a stranger who slips in and out of consciousness. The stranger claims to be the Doctor though he looks nothing like himself.
Eventually it turns out the earth is being attacked by a consciousness called the Nesterene and their minions, Autons aka automatons who look like wax figures and shop dummies.
This is one of the most comical Doctor Who stories. Pertwee has a lot of fun discovering the Doctor's new face. There are a few colorful characters like the poacher and his wife. There is a very strange scene at a Madame Tussaud style exhibit where wax figures of important bureaucrats are displayed alongside Kennedy and other notables.
The final monster, aka the Nesterene is quite disappointing but by then the viewer has had more than his or her money's worth with this story.
The other Doctor Who stories on The Doctors Revisited 1 are The Aztecs with William Hartnell, The Tomb of the Cybermen with Patrick Troughton, and Pyramids of Mars with Tom Baker. Volume 2 with 4 other Doctors is coming this fall.