"Tactique du Diable" en français, are letters from a senior to a junior devil on how to best keep under control a man of this world. If you want to know how the fight is going on and who is going to win, read the book!!!! and then take your time to ask yourself What kingdom do I belong to? and who is my king?
So true, concise and refreshing. One chapter a night is enough :) to digest and apply! Sometimes I was shocked to recognize myself so perfectly in the situations described by CS Lewis...
I bought the book but you can find the text online, e.g.
I hope you will like it :)