I just finished the new David Brooks book - The Road to Character. Two excellent chapters on Generals Marshall and Eisenhower - these are must reads.
I found this particularly interesting in the context of engineering as a calling or vocation versus a career.
"No good life is possible unless it is organized around a vocation. If you try to use your work to serve yourself, you'll find your ambition and expectations will forever run ahead and you'll never be satisfied. If you try to serve the community, you'll wonder if people appreciate you enough. But if you serve work that is intrinsically compelling and focus just on being excellent at that, you will wind up serving yourself and the community obliquely. A vocation is not found by looking within and finding your passion. It is found by looking without and asking what life is asking of us. What problem is addressed by an activity your intrinsically enjoy?"