A necessity: I cannot do without my PowerBook. My entire life's work is on it - everything I have ever written - all seven novels, every speech, every article. It includes videos of my five-year-old daughter and my diary and address book. Plus it gives me access to the web and my e-mail. People often complain about mobile communications, saying how nice it is to be out of touch. I am the exact opposite.

A luxury: I am extremely fond of my briefcase - a Hartmann made of the sort of leather that used to be used for driving big machines - rough and tough rather than smooth and Italian. I got a new one last year, and I suspect it will the last one I will ever need. I hope so because it cost around $1,000.

A memento: A few years ago, I bought a chunky Navajo silver bracelet in a shop in Sante Fe, New Mexico, one of my favourite places. I have worn it every day since. It is my comfort blanket. Sante Fe is one of those places where you feel there is a sense of deep history - even if you don't know what it is.

If only: I wish that everywhere in the world had the same power supply and telephone connection (see my first answer).

• www.h2g2.com - the online version of The Hitchhikers Guide to the Galaxy - is now open and waiting for contributions.