At dawn three days later, the Space Shuttle took off in a spectacular display of power, sound, and light.

As we boarded the plane for the trip back to Houston, I mentioned to the flight doctor that the scopolamine had worked really well. "Good," he said, "and how was your short term memory for the time you were on the drug?" Scopolamine affects the acetylcholine receptors in your brain and may impact the ability to form new memories. I thought back to the plane ride and our dramatic view of the Shuttle launch pad and told the doctor that the drug had had no bad effects; I remembered everything about the day.

But had I? About a year later, I began to think differently. During that flight to Cape Canaveral, I had read the second half of Harry Potter and The Sorcerer's Stone, the first book in the Harry Potter series. When I began the second book in the series, I discovered that I could not remember a thing about the second half of the first book, not a even a hint of Harry's brave encounter with the evil Voldemort. It was as if I had never read the book at all. So, yesterday, as I placed the motion sickness medication into my suitcase, I reminded myself to read books on the boat that it would be OK to forget!