Yes, the Gilbreths were and are real people. They have a website and everything. You can see a very brief biography of Frank and Lillian, Mom and Dad. The companion website also has pictures, a family tree, and much more.
In addition to the very amusing stories in Cheaper by the Dozen, we'll be talking more about the real family - when they lived, what it was like to live in a family of twelve children, the work Frank and Lillian did, and a lot more.
There are a lot more books than just Cheaper by the Dozen. Frank Junior became a professional writer. And, Frank and Lillian were such amazing people, a lot of authors have written about them.
This book is pretty much unadulterated entertaiment. Grab a bowl of popcorn, curl up with your copy. It's a popcorn sort of book!