My little story is that I've been writing comedy for the past year and using my initiative I knew all of this already. The information covered is VERY basic and sticks to a very derivative format, delivery followed by a punchline which includes basically every clichéd comedic technique used over the past 50 years and the self written jokes are simply awful.
I found the chapter on how to get yourself known (open mic nights etc) quite useful but again very very simple and experience combined with wits can prove all of this and more.
Books are useful for information and interpretation but with any art form, you can't learn it from a book, it's all about self expression not planning each step of a simple routine in an approach the authors use.
I'm not trying to prove my own ideas or write a book here but the best things you can do are gain influence,experience,originality and you have yourself an art form rather than a bloke telling jokes derived from his inexperienced television.
Love and typin from me x