Number of experienced/advanced PReaders on this Forum say that the book has all neccessary info. Paul says same thing. Therefore I believe that it is possible to learn PR by using the book only.
However, it's easier to learn it by course or seminar, not only because of those little details but because of the fact that it's much easier to stay motivated and on track. When using the book you have to make your own plan of progress and stick to it for some time. With seminar and course you're guided through it all. Not to mention words of encouregment.
If you tend to give up easily then the book won't be of much help. Although it contains all info neccessary you'll probably give up after a week or so when you realize it takes time to reach the goal.
Otherwise, the book is all you need to learn HOW to PR. HOW WELL, however, is up to you.