Before reading Sayre's book, I was one of those people who would walk through an art museum, gravitate to some pictures, walk past others with barely a glance, and wonder why some of the famous pictures on the wall were so celebrated. A World of Art changed all that.
Sayre writes with an almost elegant economy and a surprising amount of emotion (without getting excessive) for a text book. He doesn't try to argue or persuade; rather, he helps you open your eyes and learn what questions to ask when confronted with a work of art you're seeing for the first time. The book is loaded with beautiful illustrations chosen astutely to aid in communicating the substance of the text. The chapters are relatively short, but they're packed with content.
This was the text that accompanied an art appreciation course I took in college. I've re-read many of the chapters in the years since college - some I've read several times. I've got dozens of post-it notes stuck to the margins to remind me of things that provoked trains of thought or that clarified things I hadn't previously understood. I've even used the book to help plan some of my travel, because if I knew I'd be in a city with a museum that housed any of the works Sayre discusses in the book I didn't want to miss the opportunity to see them.
Don't let the "text book" aspect of this book put you off. This is a book that's a pleasure to read, a delight to look at, and an excellent introduction to the often arcane language of art criticism. I do recommend reading the first four or five chapters in order; after that, you can probably skip around among the chapters, but the first ones lay the groundwork for grasping the fundamental questions of what art is and - maybe most important - what are the functions of art.
I can honestly say that had I not read this book I would never have taken up painting. It has enriched my visits to some of the fantastic museums in the US, the UK, and Europe, and it's the jumping off point for what has been a long and rewarding time of further reading of books on art and artists.
Highly recommended. Don't be at all shocked to find that, after reading the book, you suddenly begin to appreciate some forms of art that you might have otherwise dismissed.