If a potato can produce vitamin C, why can't we? Within the animal kingdom only humans and guinea pigs are unable to synthesize vitamin C in their own bodies. Why us and guinea pigs? No point asking. Nobody knows.

It was an odd situation. For a century and a half, men got rid of their own hair, which was perfectly comfortable, and instead covered their heads with something foreign and uncomfortable. Very often it was actually their own hair made into a wig. People who couldn't afford wigs tried to make their hair look like a wig.

I really enjoy going to a library and spending the day doing research - to me that is the most pleasurable part of writing the science book.

Australians are very unfair in this way. They spend half of any conversation insisting that the country's dangers are vastly overrated and that there's nothing to worry about, and the other half telling you how six months ago their Uncle Bob was driving to Mudgee when a tiger snake slid out from under the dashboard and bit him on the groin, but that it's okay now because he's off the life support machine and they've discovered he can communicate with eye blinks.

I often feel I'm a disappointment to people because they expect me to be the guy in the books. When I sit next to someone at a dinner party I can see they expect me to be quick and witty, and I'm not at all.

... it occurred to me that never again would he be seven years, one month and six days old, so we had better catch these moments while we can.

Our instinct may be to see the impossibility of tracking everything down as frustrating, dispiriting, perhaps even appalling, but it can just as well be viewed as almost unbearably exciting. We live on a planet that has a more or less infinite capacity to surprise. What reasoning person could possibly want it any other way?