Time-travel indeed, right back to the First Doctor (portrayed by William Hartnell) that started the whole thing off. I was pretty small then (and usually behind the sofa!) but I still remember those early days. The Introduction explains what you can do with this book, apart from wander down memory lane: as a GM you may choose to use adversaries or even whole plots in your game, or weave bits in as part of the growing history of the Doctor whether you have a Doctor (any regneration) in your party or not.
If you want to recreate the First Doctor and his companions, there are notes on style - and complete character sheets for them - which will help you get the right feel however you want to proceed: running the adventures as they were originally presented, or using some of the follow-up ideas to create your own adventures on similar lines.
Each adventure is presented in a common style. First there is a synopsis which explains what the situation was, who the adversaries were and what they were up to, and how the Doctor dealt with them. This is followed by notes on how to run that adventure 'as is', including how to run it with a different Doctor than the first, how to adapt it or just use selected parts in your own game. Then there are more notes on creatures (NPCs and monsters) encountered, interesting gadgets and so on - you might want to use some of them even if the adventure does not suit your needs. Finally, assuming that the adventure has happened, suggestions for follow-up adventures are provided. You might want to use these after playing the original adventure or - if you are taking a more 'canon' stance and hold that the TV adventures have already taken place - use the follow-up ideas whilst letter the Doctor 'remember' the original adventure. That works particularly well if you have a real Doctor Who enthusiast playing the Doctor, one who knows a lot of the adventures that occured in the show!
There is a wealth of information here, whether you are looking for plot ideas or just revelling in detailed analysis of the early Doctor Who adventures. Everywhere is filled with snippets of use to GM and quite often to players - for example, ideas on how to play the Doctor (if you have him as a player-character) or the various companions. The GM will need to consider carefully what, if any, access he permits to this book, or it might be preferable to read certain portions to players as appropriate rather than letting them loose on the entire book.
So here we have the very first meeting with the Doctor, the first encounter with the Daleks, several historical episodes and more, all illustrated with photos from the revelant TV adventure. Alas, these are all uncaptioned although it is usually possible to figure out what they are depicting. Even if you don't intend to run any of the adventures, the comments and suggestions make it well worth reading through the lot. Of particular use to those who weren't around in 1963 to watch these adventures as they were broadcast, they are still fascinating if you do remember them (or have been watching archive re-runs).
However you use this book, it will help you to steep your game in the lore and mythology that goes to make up 'Doctor Who' in all its glory, that undefinable something that has made it endure for over fifty years. There are 28 adventures here, any one of which could keep a group entertained for several sessions.