It is a good book.
My child was the same at his age. It is what most motivates him at first, and not talking 'at him'. Whatever he says, be really interested in and take his lead. Wait for him to speak and do pre verbal activities like tickling and peekaboo. Get him to say the name of what he wants, like cookie, by saying cookie every time.
Match your speech to his. It seems silly at first, but it works! So if he only uses one word, you only use one, and then add a word when he has a lot of single words. So when he has lots of words, you can say 'Look bird' if he says bird. But if he doesn't say anything while you are out on a walk, just be quiet for most of it, if he looks at anything, say what that thing is 'Tree, tree'. Go up to the tree with him. Just say 'tree' again. Take the pressure off.
They say it helps to think about overall communication, back and forth between you and your child, rather than just speech. Any back and forth, pointing, playing, where he does something, you respond, he does something back. Like saying cookie, or pointing cookie, he gets one, you say 'yum'.