I've been collecting articles on extremophile bacteria for at least the last ten years. I find them fascinating, whether they live in boiling pools at Yellowstone, around thermal vents at the floors of the oceans, or on Mars, where NASA has been searching for them as the first evidence of life beyond Earth.

'Changes in Latitudes' began when I was looking at a photograph of a sea turtle swimming underwater. I had such a strong feeling for the beauty of this ancient creature, at home in the sea. On the spot, I wanted to swim with that turtle. I began to imagine a character who would do just that.

My first job out of college was six weeks of picking fruit alongside a dozen or so men from Mexico. The orchard was in Emmett, Idaho. The men spent almost nothing on themselves. Their paychecks went directly to their families back home.

I was astounded to learn that Alaskan caves might be hiding secrets about the earliest people ever to enter the Americas. That's when I began to picture a story that would start with kayaking and lead into the caves.

'Ghost Canoe' takes place on the storm-tossed tip of Washington's Olympic Peninsula, where I spent a lot of time hiking and exploring.