Several times a year I run a Traders’ Camp, a week of intensive classes at remote resorts. I enjoy my campers’ successes. A stockbroker became a full-time trader, closed his business, and moved to Rio to pursue a life-long interest in Latin women. A psychologist became such a successful options writer that she paid for an early retirement for her husband and moved with him to the Virgin Islands to become an expert in what she calls synchronous hammocking. A man bought a mountain in Vermont and trades from the house he built on its top. I wish all students could succeed, but it’s not that simple. How many psychiatrists does it take to change a lightbulb? Only one—but the bulb has to want to change.

To succeed in trading you need several innate traits without which you shouldn’t even start. They include discipline, risk tolerance, and facility with numbers. A big fat guy who is often drunk and can’t kick a cigarette habit is unlikely to make a good trader—he lacks discipline. A nitpicker who obsesses over each dime is too tense to live with market risks. A daydreamer who cannot do simple arithmetic on the run becomes lost when prices change rapidly.