Bernstein has first-hand knowledge of both booms and busts: His grandfather's leather factory became a growth business i伯恩斯坦有繁荣和萧条的第一手知识:他祖父的皮革工厂在1920年代成为一项增长的业务,那时汽车的普及创造出对皮革服装的巨大需求.