James Rand, a noted American industrialist who died in 1968, was, at the outset of his career, a salesman for a bank-equipment firm. Frank Munsey, the eccentric publisher and financier, was about to open banks in Baltimore and Washington. Rand called on him to sell him equipment, and the publisher cross-questioned him minutely as to the merits and demerits of all types of equipment. Finally he said, "All right, I'll give you a letter to my Washington manager. You can go to him for the order."
Delighted, Rand took the letter and hastened to Washington. He talked to Munsey's manager and got an order for $25,000 worth of equipment. In his zeal, he forgot all about the letter and did not even present it. Several days later, he suddenly found the letter and, curious, opened it. Munsey's instructions to the manager were: "Learn all you can from this man, but don't buy anything from him if you can help it."
詹姆斯．蘭德是美國著名工業家，一九六八年去世。他初出道時，為一銀行用品公司所聘，任推銷員。當時性情古怪的出版商及金融業者法郎克．芒西正準備在巴爾的摩、華盛頓兩地開辦銀行，蘭德就去向他推銷銀行用品。芒西細細查問各種設備的優點和缺點，最後說：「好吧，我有一封信，你帶去交給華盛頓那位銀行經理，請他定購好了。」
蘭德滿心歡喜，連忙拿着那封信，去華盛頓，跟那位經理洽談，獲定購二萬五千元銀行用品。他興奮得很，把那封信忘了，根本沒有交給那經理。幾天之後，他突然找到那封信，好奇心起，打開來看。芒西給那經理的指示是：「此人所知者，宜盡量問明白；其推銷之設備，則宜盡可能一件不買。」