"Best" Book/DVD on fly casting mechanics?
I am a self-taught fly caster but have been having a lot of fun for over 20y. I have had friends and now a spouse that ask me to help them out with casting, but I know I have bad habits and do not want to pass those on. What are some good books or DVD's that explain the mechanics of casting and talk about different casts? This has probably been addressed before, so just posting a link would also help.