John D. Rockefeller was a fascinating character.  A person can garner some good habits while reading this.  Rockefeller, lived by a strict budget when he first started out for instance.  This book gives a fantastic glimpse in to the life of one of America's most influential people ever.  Extremely well researched, it is a highly readable account of Rockefeller and also of his ancestors and his children and grandchildren.  I have ready many biographies and this one ranks a 10 on the scale of bios.