True North: by Bill George is a fantastic Leadership resource.  I would compare this to Leadership Challenge by Kouses and Posner which I still think is one of the greatest leadership resources still today.  However George does an excellent job with the Personal Guide.  I am not sure I would even buy the book, if I would have purchased this first.  This is a great resource for leaders and I think will prove to be useful for especially Christian leaders in any context, but would give it to my friends who are climbing the corporate ladder.