Origins of the Cybermen is an in-universe book about the early history of the Cybermen, written, and read, by David Banks. The books cover from the beginning of the Solar System up to, just before, their first invasion of Earth. Banks has tries to put together in chronological order what we have learnt from Classic Who, with small details added to fill those gaps. While it can be a little dry, overall he does a good job. This is really only for completists of the Doctor Who 'cannon'.