By making only one reference, the Broker or Owner can calculate the shortest, or most economica distances between all the major ports in the world. This has been achieved by selecting eight key "market" areas, each having its own portion of the book, in wich distnaces to all the other "markets" can be found. A special feature of this book is the pull-out map, showing and outline of the world divided as above and clearly defined for easy reference. The alphabetical index at the back of the book permits a double reference.
