The dumbest thing I've ever done with a passport was once when I flew into Bangkok. I always carry two passports, one British, one Australian. I handed the immigration official what I thought were my passport and my wife's. In fact, I had given them my two passports.
The official stamped both my passports without looking at the photos. It didn't seem to matter much at the time, but it didn't look good when we tried to leave - because they couldn't find my wife's entry stamp. We had a lot of explaining to do.
People know me as a traveller but I don't get through that many passports. They usually survive their normal span of validity. I spend half the year travelling but a lot is for business, which eats up the miles but doesn't fill the passport with exotic stamps.
Of course, I'm proud of Lonely Planet. I wouldn't describe it as an "empire" but, yes, it is one of Australia's more visible exports. India is the Lonely Planet book I am most proud of. It was one of the first books and it was a real achievement. A good test of a travel writer is whether they get lost all the time. They should, because they're always looking for a new route from A to B.
If I listed all the reasons for arguments Maureen and I have had, "getting lost" would come tops. The day we met, I got us lost on a short cut from a Leicester Square cinema to the place she was staying near Tottenham Court Road.
INTERVIEW BY JEREMY ATIYAH
Tony and Maureen Wheeler are the co-founders of Lonely Planet, publisher of guide books for independent travellers.