What his successes — and failures — have to teach other leaders. Masayoshi Son, the billionaire founder and CEO of SoftBank, the Japanese media technology conglomerate, is often cast as a dreamer, financial engineer, and speculator. But his career — which has spanned the launch of the personal computer and internet, dotcom boom and bust, the rise of China, the global financial crisis, and the advent of artificial intelligence — offers eight key lessons for leaders. They include:  turn adversity