A fun little book. I've always enjoyed optical illusions, and while some of these are old to me, others are new and neat. There are some a bit grotesque (such as skulls, or just ugly), and one or two immodest drawings, but overall decent. Many were very simple, which may be more fun for kids. Most were shapes and pictures, some words. Some didn't work so well for me, and some were a puzzle even after looking at the answer key. All pretty fun, but my favorite are generally the old/pictoral illusions.