Since the publication of the first edition of this book in 1987, offshore navigation has undergone a number of major changes, and this new edition has been thoroughly revised to meet the requirements and expectations of the current generation of offshore sailors. Some of the most important changes have been dictated by the effects of climate change on global weather and the availability of the data gathered over the last two decades by meteorological satellites. This data resulted in the publication of Cornell s Ocean Atlas, which was produced jointly with Ivan Cornell, and contains monthly pilot charts for all oceans of the world. Examination of this data highlighted some essential changes that have occurred in the global weather systems over the years. The revisions in the seventh edition were dictated primarily by the information contained in the latest pilot charts, which required a rethinking of some old established route planning tactics, many of which are no longer valid. Another important change made in this edition is the addition of detailed waypoints on some well-travelled routes, as well as the inclusion of alternative routes leading to popular cruising destinations. Compared to previous editions, where the waypoints were listed mainly for planning purposes, in this new edition every waypoint along each route is listed, enabling the navigator to plot a course for any passage from start to finish. In direct response to current navigational methods, most routes, and especially those leading to popular cruising destinations, have been redesigned to provide essential passage planning details. Also, new routes have been added to areas rarely explored until recently by cruising yachts, from Greenland and Micronesia to China and the Northwest Passage. One new feature added to this edition is that of windgrams depicting a summary of wind conditions for the month when passages are undertaken along some of the most commonly sailed routes. The windgrams are a synthesis of individual windroses as shown in the pilot chart published in Cornell s Ocean Atlas.