Weber's theory is highly questionable, and widely disputed by historians of the economy. Weber believed that capitalism was born in Prussia in the nineteenth century, in doing so forgets the role of Italy, the Templars and the Champagne fairs in the Middle Ages.
He studied a group of Protestants, and it then includes all Protestants in her study.
It is a true sociologist of work: starting with an idea and we try to demonstrate it. The problem is that the facts are against this idea.
The book is still widely cited, and still largely questionable.