March Books 17) Companions: 50 Years of Doctor Who Assistants, by Andy Frankham-Allen
Second paragraph of the third chapter:
During the rest of their travels with the Doctor, we learn very little about Ben & Polly, even though they continue with him for another six adventures. It is a curious thing that from the start, despite having witnessed the Doctor's 'renewal', Ben refuses to accept that the Doctor is indeed who he claims to be. Once again Polly is the voice of reason, willing to accept what she has seen, even if she cannot really understand it. Throughout their adventure on the human colony on Vulcan (The Power of the Daleks) Ben continues to be irritable and highly strung, while Polly opts for calmness. It is only when a Dalek recognises the Doctor that Ben finally accepts this strange man in the frock coat is the same old man he had come to trust.
A fannish guide to all the Who companions from Susan to Clara, up to the middle of 2013. Not really very deep, and the author has some very weird ideas about Rose Tyler. Benton and Yates, and later Chris and Roz, are simply omitted. Also, although the "Expanded Universe" (a term I've never previously seen applied to Who) is covered in some depth, publication details for the short stories are usually omitted and there is no bibliography. Graham Sleight was able to make bricks out of the straw of The Doctor's Monsters, and I should think it fairly easy to repeat that exercise interestingly for the companions; but this is not that book.