Rancher Oscar Thompson, who worked cattle near Hebbronville, Texas, was ready to trust his son, Webster, with the family business. By lantern light, he scribbled twenty-one simple rules for the boy to follow when he took over as boss to a team of ten cowboys the next morning, driving twenty-five hundred head of cattle to market. These salient pieces of management advice, written in the 1880s, are as useful for managers today as they were then.

Now, consulting team Tim and Dana Frazier build upon these bits of wisdom and bring them to modern business. Adding their own insights from...