I bought this book on a recommendation, as I would *never* purchase a book on personality that claimed to segment the human race into 4 types. Upon reading it, i was quite taken aback at how recognisable each type was, and furthermore, as to just how much of one's personality can be covered through this almost obscenely simple 2 by 2 matrix. The writing is very astute, and delivers 4 internally consistent personality types whom are entirely believable as having quite opposing views of the world, with the resultant differences in behaviour. As is pointed out, these types are of course not mutually exclusive, yet the power of this book for me was how apparently negative traits in people are partly resulting from their 'type' and partly resulting from my perception of their type, the latter stemming from my own type! A great lesson in humility and reality i think.