If you find that some comments on this book seem too enthusiastic, think again. This book is simply outstanding and it is undoubtedly one of the jewels of my personal library on photography, which is nevertheless quite comprehensive. Why? First, because it is very well presented, with many photographs, illustrations and diagrams helpful. The paper of the French edition of a pretty white satin showcases a clear layout and "classy". Impeccable. Secondly, because the author - Syl Arena - is a REAL teacher. From the first chapter, it gives you the essential rule of the flash picture (it is the opening that sets the flash output and speed, which controls the lighting in the background) and explains in two spoon pot shots at how to take your first pictures with your Speedlite. Then, lesson after lesson, it is dedicated to helping you improve your images starting with explaining how the light (square theory, temperature), the importance of shadows (sharp, diffuse), the orientation of the lighting (contrast), modes ETTL / Manual / Multi, the high speed synchronization, stroboscopic photography, etc. And he does that by using many examples that can instantly understand his point. As the French translation is also excellent (I noted very few dambiguïtés), this book is read with pleasure. Note that it also offers real-modes explained Placement of Speedlites and their useful accessories ... while denouncing those who are much less. True, this book is entirely devoted to Canon flash units, but in fact at least 80% of the book can be used by all followers photographers flash light, even the henchmen of Nikon (a sect to which I belong Occasionally, I admit). In short, all this gives us just a great photographic technique treaty. Start saving, you will soon buy other flashes!