I have't finished the book, but I found a section about the Cynics, who were the minimalists of philosophy. It goes like this:
The story goes that one day Socrates stood gazing at a stall that sold all kinds of wares. Finally he said, "What a lot of things I don't need." This statement could be the motto for the Cynic school of philosophy, founded by Antisthenes in Athens around 400 B.C. Antisthenes has been a pupil of Socrates, and had become particularly interested in his frugality.
The Cynics emphasized that true happiness is not found in external advantages such as material luxury, political power, or good health. True happiness lies in not being dependent on such random and fleeting things. And because happiness does not consist in benefits of this kind, it is within everyone's reach. Moreover, having once been attained, it can never be lost.
The best known of the Cynics was Diogenes, a pupil of Antisthenes, who reputedly lived in a barrel and owned nothing but a cloak, a stick, and a bread bag. (So it wasn't easy to steal his happiness from him!)
One day while he was sitting beside his barrel enjoying the sun, he was visited by Alexander the Great. The emperor stood before him and asked if there was anything he could do for him. Was there anything he desired? "Yes," Diogenes replied. "Stand to one side. You're blocking the sun." Thus Diogenes showed that he was no less happy and rich than the great man before him. He had everything he desired.
The Cynics believed that people did not need to be concerned about their own health. Even suffering and death should not disturb them. Nor should they let themselves be tormented by concern for other people's woes. Nowadays the terms "cynical" and "cynicism" have come to mean a sneering disbelief in human sincerity, and they imply insensitivity to other people's suffering.