It's difficult to describe what I call "properly" without doing it a diservice but the original book is called "Use Your Head" by Tony Buzan and I would highly, highly recommend it. The first half doesn't really touch on mind mapping and is more on how memory works but that sets up for the mind mapping section and is just as (if not more) valuable.
It's an old book, I read my Mum's copy when I was 14 and it was hers from uni but it is great.