This book is written for chess friends who are beginners or hobby players without much experience and who want to improve to lower club level. If you are already somewhat stronger you may not like the idea of learning from scratch. But sometimes going a step back in order to take two steps forwards is a good idea.
To play chess well one has a lot to learn: opening, middle game, endgame, tactics and strategy etc. Where to begin? In my opinion tactics are the most important area. I always advise players with a rating under 1700 to study tactics, learn some basic endings and start analyzing their own games. That is a good way to reach a higher level.
Tactics are the main topic of this book. Tactics are not only the most exciting and enjoyable part of chess but also the fastest way to improve. On the following pages you will find an introduction to the most frequent tactical motifs and a lot of exercises for each of them. My guess is that in practice you will need about 50 examples or exercises for every motif to make you familiar with it. If you know the motifs you can not only win more often but, even more importantly, recognize the possible threats of your opponent earlier and defend yourself better.
Tactics are helpful for players of all categories. I myself and many of my grandmaster colleagues regularly solve combinations and studies, especially as preparation for a tournament to give the brain a kick.
Have a lot of fun while studying chess and enjoy your improvement!