The Witch Hunters
The Witch Hunters by Steve Lyons is a book following the exploits of the First doctor, Susan, Ian and Barbara in the town of Salem during the infamous witch trials. This is an excellent book and one that I would thoroughly recommend. It manages to successfully maintain an accurate characterisation of the time-travellers while building on and developing their characters. Even the Doctor is given the opportunity to lay certain ghosts to rest. This is done within the context of an intelligently-written story which manages to educate, entertain and build a good level of suspense. It is true to the programme of the period, drawing on the little amount of back story and history that the programme had already managed to develop during its first series, such as the fragile relationship between the Doctor and his two abductees, and the telepathy which Susan had demonstrated during the Sensorites. Even the fast-return button makes an appearance. It is well-paced with dialogue true to the characters.
I won’t include spoilers but would encourage you to read this as an example of an intelligent Doctor Who novel.