This book is an excellent resource on the following Christian Heroes, most who are/were missionaries:
Mary McLeod Bethune
George Washington Carver
Jonathan & Rosalind Goforth
The book's format covers a 2 page biography on the hero, then follows up with separate chapters on character qualities specific to the individual (i.e. George Washington Carver's biography is followed by chapters on perseverance, resourcefulness, and service). An added bonus is that there is a list of all the character qualities in the back of the book. So if you're looking for examples of a specific character quality the list is a wonderful resource.
I found this book very interesting, especially since I have never heard of the majority of these people. The age level for those who would be interested would probably be 3rd grade and higher. There are no pictures, other than drawings of the person at the beginning of the biography, so it could be quite boring for preschoolers and early elementary grades.