Hi there and welcome. Sounds interesting about your book. I would say that you should make it fictional. If you were to make a book about "how to" you would need a lot of experience on the subject. Maybe have hundreds of lucid dreams under your belt. See all of us selftitled "gurus" on these forums, nobody would buy a book written by us - unless we really had something new and at the same time tried and tested experiences to write about. If you make it fictional you could maybe get away with writing a book that could motivate people to get into LD's...

just my thoughts...