I saw it myself!” – we say and the argument is over. Our eyes – what could be more reliable? But sometimes the eye does not see exactly what actually exists, or it sees something that is not there at all. Sometimes we encounter illusions – tricks that our eyes and brain perform over and over again. It seems that illusions are something exceptional, rare. But that’s not true. Under certain conditions, illusions are natural phenomena. This book is about the tricks of our vision. We have collected the most famous and impressive illusions and will try to find an explanation for them. However, some tricks of vision have still not been explained by science and remain a mystery for us to solve.