This book helped me in practically every way. I went from Palermo to Milazzo to Alicudi to Messina to Taormina to Catania. And the book had ample information for every situation I found myself in. It was most helpful to me when I was traveling. The information on how to physically get from place to place (trains, buses, ferries, taxis) is what I used the most. Get a map from the local tourist office; the book tells you where they all are. Also, I saw a ton of people with the same book! Must be a popular guide.
Of course, I learned more about Sicily by seeing and doing than by reading, but this book is a great reference to have. Highly recommended.