In the late 1970s, the “Classic” Doctor Who episodes had come to the U.S., largely on PBS stations and other non-network broadcast channels. That wasn't how Harlan Ellison got hooked on the show, though. He was introduced to it by fellow writer Michael Moorcock, an English sf and fantasy writer of great imagination and greater taste.
Thus, Harlan Ellison came to write the introduction to this volume, which contained three novelizations of Dr. Who stories from the period in which Tom Baker played The Doctor, to the delight of fans all around the world. The stories of that time period included both the “classic” aliens of the series, and various one-shot creations almost suited to mild horror movies.
The three stories contained in this book, Doctor Who and the Genesis of the Daleks, Doctor Who and the Revenge of the Cybermen, and Doctor Who and the Loch Ness Monster, captured the period very well, and writer Terrance Dicks did a delightful job of capturing the mood of the stories. This was the period of Sarah Jane and Harry as the companions, and Brigadier Lethbridge-Stewart and U.N.I.T. as the official British response to the weirdness of the space age and its tendency to attract creatures from other worlds.
If you've never seen a Tom Baker episode, these will give you a taste of what they were like. If you've seen these episodes in the distant past, they will provide a nice reminder of what the show was like back in the "classic" days. The stories aren't perfect, but they're entertaining, and a good introduction to the show from that period. If you like these stories, then by all means find a way to watch those shows and the others that went with them!