This is a Doctor Who volume whose time has come (pun not intended). Being a bit of a Whovian, as well as a writer in the genre, I own some other recently-released reference works: the excellent Who-ology and the Doctor Who Character Encyclopaedia chief among them. These are excellent and definitive works, but the key thing is that - by their very nature - they're not readable. Yes, they're lovely to dip into or browse, but you can't digest the contents. And it's all just terribly confusing and a bit much.
This is the big plus of Cameron K McEwan's seminal work: you can sit down and read it with a great deal of pleasure - no matter what your age or your level of knowledge. The author gives us a wonderful narrative of the story to date - something I've not seen anywhere else. In no time at all (stop me!) you get a start-to-finish overview of the entire series - the characters of the Doctor's incarnations, their companions, travels and adversaries.
With over fifty years of storylines, things can get a little complex and hard to understand (even the BBC scriptwriters have had trouble remaining consistent within the storyline). Sure, if you need a definitive answer to a specific question, then Who-ology is terrific. But even if you're as old as me and have memories of cowering behind the sofa to Peter Troughton's adversaries (the second Doctor, to the uninitiated) then you're going have problems getting a proper feel for how the series - with its twelve incarnations of the Doctor, and a vast cast of companions and monsters - has unfolded.
Read it for fun and clarity - you'll get more out of every episode you watch. (Afterthought - they should give this to the scriptwriters so that they don't keep tripping over the storyline...)