Is there any must-read book before starting personal investing?
I am looking for textbook(s) in order to get into personal investing. After a quick research on Amazon I found two types of books :  The "personal investment" books, promising big incomes with almost no effort like this one : https://www.amazon.fr/Stock-Investing-Beginners-Investors-Advantage-ebook/dp/B07GD4PCRC/ref=sr_1_17?__mk_fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=personal+investment&qid=1624608449&sr=8-17, seems very concrete but I am not sure about the seriousness of the work. The "portfolio theory" books, like this one : https://www.amazon.fr/Portfolio-Theory-Management-Maciej-Capi%C5%84ski-ebook/dp/B00KL8CDR4/ref=sr_1_2?__mk_fr_FR=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=portfolio+theory&qid=1624608761&sr=8-2, wich seems more interesting from a conceptual point of view in order to develop a deep understanding about financial markets but maybe not so useful for elaborating concrete investment strategy  I am looking, if possible, for a reference offering in the same time a conceptually rigorous (I am doctor in statistics, so I'm not afraid of math) introduction to finance and investment and a presentation of concrete and up to date strategies valuable for a individual who want to invest a small amount of money. Thanks in advance