After the age of seven, I began living between my dad in Alaska and my mother in Baltimore. Every three or four months, I would fly the 5,000 miles between the two. And having grown up in Alaska, Baltimore was astonishing.

The tough thing is how to cultivate a life where the paramecium of happiness gets a lot of chances to get out and swim and make more paramecia. That seems like an obvious universal goal for most humans.

It feels like people talk a lot, in their relationships and in therapy. But my family wasn't like that. My dad wasn't and I wasn't. Things were said, but via the language of action.

Even as my family fell apart and things were at their most hopeless, my dad and I found a lot of happiness in the wilderness - sleeping on the cold gravel and killing as many things as we could get our hands on. Even as my mom got progressively more crazy, we found a happiness, in flashes.

After my parents divorced, my father remarried and my brothers were born when I was twelve and sixteen. I was thunderstruck at these kids. The "baby-ness" of them. Their toes. I had never been around babies before.

There was always some germ of joy, some little paramecium of happiness wriggling around, waiting for a chance to get out.

When you're looking around for metaphor or simile, I do think it's often helpful to keep inside the world of the book, to gather your comparisons from the stuff particular to that world - be they king salmon and aviation fuel, or pot roasts and spatulas.