If all you are searching for is the basics then reading a book might be for you. (printed how many years ago...?) But no...one does not "need" to go buy any book or video. They are available free on the web.
For example:
Greg Green - The Cannabis Grow Bible (4th Edition)
Marijuana Growing Guide Free Library
POT-TV: Marijuana Man Grow Show
Regardless...you can get much better/up-to-date info here.
Plus, with a book...can you write-in your questions or observations, and have the author reply overnight? Can they troubleshoot your problems for you? Can they recommend the latest in nutrient systems or lighting to best fit your situation...?
For every leaf you trim, you have wasted that much energy potential. (photosynthesis and nutrient storage) One isn't so bad, but with every leaf you pluck, there is a significant proportion of the total leaf area now gone.
Pluck the leaf, and it's associated bud stunts.