This is a terrible corruption of Stoicism.
The Stoics tell us that things happen, but that they are made worse by our attitude to them. To be unwell is not pleasant, but we magnify its' effects by dwelling on our misfortune, or regarding it as a personal attack on us.
But it also teaches that desiring things we cannot have, or that are not in our own power to obtain, is also a key cause of unhappiness.
The Stoic is content with what they have, and because they don't worry about things they cannot prevent, or desire things they can't get, they are free of fear and stress.
This book, and others like it, twist Stoic philosophy into something that, instead of teaching us to control our thinking, makes us believe our thoughts control the world.