Wikipedia says: The Emperor Wears No Clothes is a non-fiction book written by Jack Herer. Starting in 1973, the story begins when Jack Herer takes the advice of his friend "Captain" Ed Adair and begins compiling tidbits of information about the Cannabis plant and its numerous uses, including as hemp and as a drug. After a dozen years of collecting and compiling historical data, Herer first published his work as The Emperor Wears No Clothes in 1985. The eleventh edition was published in November 2000, and the book continues to be cited in cannabis rescheduling and re-legalization efforts.
Get it at your local library or order it online. (I always go for FREE when I can) Although this book is what I call a "keeper" - One that I use over and over again.