Masayoshi Son is man of extremes.

His $20 million bet on Alibaba Group Holding became the most successful of all time when it swelled to more than $70 billion after a decade. He also lost $70 billion of his net worth in the dotcom crash, but then managed to raise one of the biggest investment funds of all time ¡ª the $100 billion Vision Fund ¡ª in 2017. The 67-year-old has been on a roller coaster that would put most mortals in therapy for life.

He is unapologetically dramatic, once threatening to set himself on fire if he wasn¡¯t granted a telecom license in Japan and shoots from the hip in business deals. He says he backed Alibaba because of founder Jack Ma¡¯s ¡°strong eyes, shining eyes,¡± and he convinced the crown prince of Saudi Arabia to put $45 billion into his Vision Fund in a single, 45-minute conversation, by offering him ¡°a Masa gift, a trillion-dollar gift,¡± according to Son¡¯s 2017 interview with Bloomberg¡¯s David Rubinstein.

So unusual is Son ¡ª known as ¡°Masa¡± ¡ª that he is now the subject of two books, one by former Financial Times editor Lionel Barber and another by Alok Sama, a former president of Son¡¯s telecommunications and technology giant Softbank Group International. Both paint a portrait of a global maverick who never seems to sleep, but it¡¯s Sama¡¯s book ¡°The Money Trap¡± that looks closely at Son¡¯s potential impact on the booming AI market. ¡°Masa Son¡¯s ambition is to be (AI¡¯s) high priest,¡± writes Sama.

¡°He¡¯s not a gambling man,¡± Sama tells me, adding that Son has made 10 times what he lost on WeWork through his investment in Arm Holdings, the chip-design firm that¡¯s now at the heart of his AI ambitions. ¡°He¡¯s living in the future.¡±

Son founded the Vision Fund to capitalize on the so-called singularity, a hypothetical threshold sometimes defined as being the moment when AI surpasses the human brain. When he spoke at Softbank¡¯s annual general meeting this past summer, Son said he¡¯d become obsessed with realizing ¡°artificial super intelligence¡± and was born to make it happen. His past investments were just a warm up.

No surprise then that Son has been on an AI tear. Last month, he invested $500 million in OpenAI through his Vision Fund, having missed out on the AI company¡¯s previous funding rounds. Earlier this year, he led a $1 billion investment into British self-driving car maker Wayve and put as much as $20 million into Perplexity AI, which is going head-to-head with Alphabet¡¯s Google Search. Son recently told investors he¡¯ll continue fishing in areas like autonomous driving, data centers and AI robotics. He¡¯ll have rich pickings, with dozens...