There are two kinds of guidebooks: There are the ones you use for planning a vacation, for background, history, photographs, insights into the people, the language, and various aspects of the society. This kind of guidebook is frequently lavishly illustrated -- though you might not want to take it with you. THE INSIGHT GUIDE TO ICELAND belongs to this category. It is printed on a nice glossy paper stock and weighs almost 2 pounds! That's about 8% of what I allow myself for total baggage for international travel.
The other kind of guidebook is indispensible for its wealth of detail: opening hours of attractions, accommodations, restaurants, phone numbers, addresses, websites, e-mail addresses, and other info you would use "in country." Lonely Planet and Rough Guide are probably the best examples of this category: I take a razor blade and neatly remove the sections I don't need and pack the mutilated remains with my bags.
When I travelled to Iceland, I left my copy of the INSIGHT GUIDE at home. But I keep it to show friends where I have been and what a particular place looked like when it was NOT rainy or foggy. The photographs in this book are superb; the essays are of uniformly high quality; but it is short on up-to-date details. On the other hand, if you use it for planning or just armchair travel, you can't surpass it. It looks nicer than the Landmark Guide and the text is more interesting.
As Lord Dufferin wrote some 150 years ago in LETTERS FROM HIGH LATITUDES, Iceland is a very different country when the sun is shining. Of course, you can't always get that: I saw some spectacularly awful weather at Stykkisholmur and Lake Myvatn, but I can appreciate a book that shows a country wearing its best finery. I plan to keep this book and refer back to it to plan future visits to this fascinating land.