The book
Allen published this in 1903 and called it suggestive rather than explanatory. A little volume, meant to stimulate, not a treatise. Mind, in his image, is the master-weaver of character and of circumstance. A person who has been weaving in ignorance can start weaving on purpose.
Seven chapters, one chain: thought, character, circumstance, body, purpose, achievement, ideals, serenity. He will not let you work on circumstances without touching the thinking that keeps producing them.
The chapter to argue with is the one on circumstances. His claim is not that bad things do not happen. It is that conditions disclose something, rather than merely landing. Read as a system, the book promises more than forty pages can carry. Read as a prompt, it holds.
Purpose is his answer to drift. Thought without an aim scatters into worry.
A summary states the weaver and moves on. The edition stays on one condition you are treating as weather, and it will not accept agreement in the abstract. You name the condition, or you say where he is wrong. Both are allowed.
Serenity, in his order, is what is left after the aim has been held. The edition will not start you there.
It will not turn the book into a diagnosis. Allen was not writing therapy, and the circumstances chapter is the part to resist when a real constraint is being blamed on your mood.
Claim it on the book page. As a Man Thinketh.