You finish the first chapter delighted to have discovered your 'type'. You expentently read the next part and end up wondering if you were right in your self assessment from the first. And thus you proceed, each chapter prompting a re-read of all the previous ones, by confusing you with all sorts of contradictions and unhelpful generalisations. And your reward for this perseverance? A long and broad list of possible careers, 90% of which are repeated for the other three of the sixteen personality types you narrowed yourself down to, leading you to think that personality probably doesn't even matter. If, as I suspect, these career listings are taken from a database of what jobs people of certain types do (rather than what they should do), there's a fair chance they probably all need to read a good career guidance book.
I hope this is just a bad 'Myers Briggs' style book. If it is representative of the theory, I'm far from convinced. As for the 'career' section, it is so generalised that most intelligent people will glean one thing from it: A wide variety of people could do the same job, but they may enjoy it for different reasons. How useful was that?