"Mastering data will improve your team's performance, particularly your starts, and lies at the heart of your strategy and tactics. As a racing professional and tactician I have become increasingly dependent on that data and those who help to manage it. This book is fundamental reading not only for any aspiring navigator but I would suggest for all members of the crew. Good navigators need to be very well prepared, well organised and good under pressure - I would suggest that reading this book is a pretty good place to start that preparation!" (Ian Walker, double silver medallist & Volvo Ocean Race winner)"Electronics systems on board have become more advanced and more affordable, and learning how to use them and interpret the numbers is key to every modern keelboat sailor who wants to compete." (SailWeb)"It reads really well, and really highlights how being a navigator is part science, part 'art'. It's a high quality product." (SailingPerformance)"An eye-opening book for those of us who have not experienced the complex systems of a modern racing yacht - and a useful one for those who have." (Yachting Monthly).