While I was a student at MIT, I had the opportunity to work in the school's Admissions Office for two summers. During my first summer I met "Doc" Edgerton. I think he was partly responsible for my interest in teaching and largely responsible for my lifelong interest in students. Doc's accomplishments were astonishing. Some of the highlights of his career were: inventing the stroboscope used for stop-motion photography; being the first person to photograph the wing movement and flight patterns of hummingbirds; developing nighttime aerial photography during the Second World War; working with the famous oceanographic scientist, Jacques Cousteau, on numerous expeditions; inventing side-scan sonar to locate objects on the ocean floor; designing a device that can be used for continuous seismic profiling of the bottom of the sea; designing an elapsed-time photographic system that can photograph underwater events normally too slow to be seen; and locating the sunken Civil War battleship USS Monitor.

One of the less publicized aspects of Doc's career was his unintentional disruption of tours that the Admissions Office gave to prospective students. The tour groups would walk past Doc's laboratory, he would invite them in to look around, and the tour would end because no one wanted to leave. Doc spoke softly, but the twinkle in his eyes and unbridled enthusiasm for his work could be seen and felt by all. He would explain his latest ideas and list all of the related unsolved problems. He would ask the prospective students how they would approach the problems or use an invention. No, it wasn't a test. He sincerely wanted to hear their answers.

I was asked to talk to Doc and ask him not to disrupt the carefully planned tours. I decided to tag along with a tour group and experience the problem firsthand. As expected, Doc invited the group into his laboratory and started explaining and questioning. Within a few minutes the tour was over. I waited nearly an hour until the last visitor left and then spoke with him. He told me that talking with new young people was the highlight of his summer. "I explain my problems and ask them for ideas that might solve them," he said. "My problems need the new ideas of fresh minds; the old ideas of the older minds have been tried already and were unsuccessful. It is the new minds of the young people that will solve these problems. If my colleagues or I could solve them, we would have already done so." I decided not to ask him to stop disrupting the tours.

The books in the REAL Mathematics™ series are written with the spirit of Doc Edgerton. Many problems of mathematics are discussed - some that have been solved and some that have not. From the young minds that read these books and consider the problems, new insights, new solutions, and penetrating questions are likely. Never underestimate your own abilities. Enjoy your adventure!

The REAL Mathematics™ series combines recreational mathematics and modern technology. You will almost certainly need a simple calculator to do many of the problems. If you can use a computer, that's even better. However, you do not need to use a computer to get the full value of the material.