You can learn hair techniques from a book but mostly in regards to hair styles. If you're actually interested in cutting hair, it's best to take classes.
There are many books that can teach you hair styling techniques, but just like driving or cooking nothing can be perfect the first few times so practicing on manikins or real people will help you get techniques down and also help you figure out your own style of doing things.
Sometimes I suppose you can. Usually people using books, have experience with hair cutting. If you do think you have talent, nurture it and go get into beauty school. If you think your good, educate yourself the right way.
