I've read this book over and over and over. It's falling apart.
I have enjoyed it. It's been my first experience with typing and I find it extremely thorough.
He is a master at categorization.
My complaints with it are two fold:
1. He has a bias against S's... that is to say that he likes N's quite a bit more.
2. He's very implicit about certain faults that humans fall into being traits of personality. Though he is correct that if those people do give in to their worse nature, they portray those traits in spades. (this is where complaint #1 usually comes into play.-He values N abstractness, and finds frustration with S reality.)
Please Understand Me II Introduces the 4 intelligences: SP Tactical, SJ Logistical, NF Diplomatic, and NT Strategic, which he bases upon interest practice skill. Saying basically that Certain personalities have tendencies towards certain intelligences, which makes sense. If you have difficulty typing people this is an excellent way to determine their type. However, it is not foolproof as it is possible or necessary for some to take another intelligence as their main. This doesn't happen often, but it can. He also qualifies it with 'normal development'. For instance, my development was not 'normal' as I had an extremely controlling ESTP father who used tactics. Therefore I am an ENFP who had to learn tactics in order to survive and get things I needed and wanted. There was no place for diplomacy in this narcissistic regime, so I learned to fight fire with fire. (NOT THAT TACTICS ARE BAD!)
One trick to the book is that it's something you can/will want to skim over and over, once you learn his definitions and meanings for certain words- and the application there of. It's harder to get into initially, but once you get his language down it's extremely insightful.
David Keirsey is an INTP. I would highly, highly recommend the book to any rational (NT), as he seems to have then very thoroughly understood. He is a genius no doubt about it.
I also enjoy the titles he gives to each type.
To be honest I have no *idea* what you guys are talking about when you put A capitalized letter next to a small case one eg Ti. I have been a little curious.