This book results from sailing for 25 years at sea at different ranks, including 15 years of command and more than 20 years of teaching in maritime universities, colleges, and simulators. Lack of knowledge and misinterpretation of the rules are the reasons for Most collisions at sea. The author tried to interpret the rules of the road practically to be understandable both in the classroom and at sea, to make this book enjoyable and valuable for maritime cadets at the maritime colleges, for deck apprentices at sea, and for deck officers of watches to study, learn and even increase their knowledge. The main aim of writing this book is to improve the safety of navigation and life by avoiding collisions at sea.The author did his best to combine his knowledge and practical experience at sea and in different universities and simulators to write this booklet in a language that is easier to understand, especially by maritime cadets worldwide.The unique part of this book is the coloured pages showing the navigational lights of different vessels. All the photos belong to the author, and most of them have been created in the bridge simulator and then photographed.