I've been reading this book to plan my gap year, and I have to say it has been incredibly useful. It has absolutely all the vital information you need to know before you set off. For example, it has all the obvious info on visas and vaccinations, but also some of the issues you may not have thought of, like what to do with your house while you're gone. Of course it is aimed primarily at budget travellers, but I would say it is still of use to those taking a more comfortable route around the world. I've now loaned the book to my travel partner, and she certainly agrees, it is a brilliant place to start planning your life-changing trip!
I would also reccommend, for more detailed planning of your time in various continents, the rest of Rough Guides First Time series:The Rough Guide First-time Asia (Rough Guide to First-Time Asia)The Rough Guide First-Time Latin America (Rough Guide to First-Time Latin America)The Rough Guide First-time Europe (Rough Guide to First-Time Europe)A Rough Guide First-Time Africa (Rough Guide Specials)