Unfortunately this is one of the later editions, "revised" by Carnegie's wife after his death.

I would only recommend reading earlier editions: http://abebooks.com/servlet/SearchResults?an=dale+carnegie&tn=friends+influence&yrh=1960

What was changed in the later editions?

PG recommended this in one or another essay, and I found it a rather suspect claim, but having started reading the PDF it seems like it might be helpful, if one has the strength of character to truly change.