I can see some of the criticism for "The Edge of Destruction" being fairly valid. Before purchasing and viewing the tape I had picked up the book version that I used to have when I was younger and never got around to read.
Both "Edge" and "the Doomsday Weapon" are magnificent examples of some of the great writing that came out of Dr. Who. To say the least I enjoyed reading it immensely and was so impressed by the book I ordered the tape to see how they would have adapted certain scenes. My first disappointment was the length, at least half of what should've been used to truly tell the tale. It is the slow and somber tension that carry's the book to the height it reaches, which is managed with less than 150 pages.
Dealing with the interaction and energy between the four characters, fiercely dealt amongst from the vantage of the schoolteachers and their captors. The filmed version manages still a wonderful cap of the story that won't disappoint. Without hesitation I would recommend reading the book first and enjoy it in the fashion I feel it was meant to be.
Although the sets are lit slightly more than one would have hoped, it is a shining example of the superb storytelling and character building that Dr. Who was founded on. This episode is more or less a corner stone to the future adventures as a confined story in order to expand the whole series.
Also the missing years tape is fantastic and far beyond what one would expect. Many great background stories and lost clips to even the value.