Not content with one copy I got my club to purchase another seven. A few months later the transformation poolside is noticeable - teachers & assistant teachers refer to the book all the time and create their own mix of drills when teaching right through the courses we deliver. We have our favourites. All work. The progressions into each competitive stroke could not be better, there are fun practical drills too ... and of course dives & turns. My wish is for a large format version that I could better use poolside when demonstrating to swimmers. Great stuff.