This is an interesting book about the ways our illusions and beliefs can play tricks on us. The title comes from a psychology study where people were asked to watch a basketball game and count the passes made by one team. Test subjects watched and counted for one minute. At least half of them never noticed the person in the gorilla suit who walks across the court. However, common belief is that everyone should have seen the gorilla because it was right in front of them.
Other illusions the book addresses are the illusion of memory (that a strong, clear memory must be a true one), the illusion of confidence (that someone who shows confidence must be the best person for the task), and a few more.
The book is quite readable, not at all dry or textbookish. Recommended for anyone who is interested in how the mind works.