I recently read Martin's Big Words by Doreen Rappaport to my third graders and they LOVED it. Martin Luther King Jr. is a famous American that third graders in VA must learn about. After have discussed MLK Jr. for weeks and read many books about him I was surprised to see my students so engaged as I read this book. This illustrations in the book (by Bryan Collier) are phenomenal and after I finished reading the book the students keep asking to borrow it throughout the day to reread it and study the illustrations.
The book tells the story of Martin's life from childhood through his death. Each page has one of his quotes (that applies to the text on that page) in big colored letters. A couple pages into the book I stopped to explain to my students that the big words (as hinted by the title) are words that MLK Jr. actually said, that is why they are in quotation marks. Once I made this connection for my kiddos the light bulb turned on and they thought the connection was so cool.
I highly recommend you check this book out! Your kiddos will love it and it has received awards as a Caldecott Medal Honor Book, ALA Notable Children's Book, and of course a Coretta Scott King Award Honor Book. (This book has won many other awards as well!) Enjoy!