I'm French and found this website as I was looking if the Lafay book exists in English for a friend living in Australia.
Apologies if I make mistakes writing in English.
I just wanted to give you some info about this Lafay book as I can understand your questions. I am a girl who only believe to what I see, and don't like all this stupid books saying "loose weight in 3 days for all your life" etc...
My husband is going to a fitness center every day during lunch break. After 4 years he was disapointed as he couldn't see any real result and really don't want to eat medication to be "stronger" or have more muscles.
We are both playing volley ball in regional teams and wanted to find a way to have more force to shoot the balls and jump higher.
One day he came at home with this book. I was laughing at him. Finally I had to admit that the transformation was here. After 4-5 months, he won about 10 kg muscles. Now he weighs about 87kg for 1m82 but don't take more kilos. In my case, I was a little bit "fat". I didn't loose weight but lost centimeters. There is a method for men and another for women, there is also one for people wanting to do more body building.
There are in France lot of critics too about this book as it is not expensive to buy compared to an annual subscription to a fitness center. There are people who only believe to the halters system, those who use both with the book and people using only the book.
I don't know if now the book has been translated into English or not. Here is a link to the forum in French where girls and men are writing their impressions, looking for advises, and some of them are posting pictures of them. So you can check that it is not a fake or spam :
and for girls :
From what I know, the people having the most impressive results have a nutrition program too. It is not my case as I want to continue eating from everything when I want (being reasonnable of course).
I think to see that it really exists, when you go to google and enter Methode Lafay, you have to search in the French pages to find it.
I don't say that it is better than another book or what. It was just to say that it really exists and works without eating steroids or other drugs, and without privation with food. I believe of course that other books exists and their programs / methods are working too.
Wish to all a good day and all the best in your sport's activity.
Greetings from Paris.