New Delhi, Sep 13 : Tesla & SpaceX CEO Elon Musk got upset when Amazon founder Jeff Bezos did not invite him to visit Blue Origin's factory, Musk's biography by American author-journalist Walter Isaacson has revealed. The new biography, titled "Elon Musk", highlights the early stages of his relationship with Bezos when he invited the Amazon founder to tour SpaceX in 2004, reports Insider. Following the tour, Musk sent Bezos a "curt" email expressing his disappointment at not being invited to see Blue Origin's factory in return, according to Isaacson. A surprised Bezos then responded to the email with an invitation. According to the biography, after touring Blue Origin, the couple had dinner with their then wives, MacKenzie Scott and Justine Musk. Apparently, the dinner did not go over well due to Musk's seemingly unwanted advice to Bezos, as reported in this book and in Christian Davenport's book, "The Space Barons". However, it's unclear what the advice was, the report mentioned. Since that dinner, the two have traded digs publicly, sparred over their space ambitions, and traded places as the world's richest people. According to the Bloomberg Billionaires Index, Jeff Bezos is the world's third-wealthiest person, with a net worth of $165 billion, owing largely to his stake in e-commerce giant Amazon. Musk currently holds the top spot on the list, with a net worth of $242 billion. Meanwhile, the biography also revealed that Musk and billionaire philanthropist Bill Gates got into a verbal spat after the Tesla CEO confronted the Microsoft founder over shorting the electric-car company's shares last year. Isaacson wrote that in early 2022, Gates spoke to Musk and said he wanted to "come see (him) and talk about philanthropy and climate" at a meeting. The meeting happened at Musk's Texas plant where the SpaceX owner confronted Gates over the decision to short Tesla stock. Musk said in April 2022 that Gates had taken a half-billion dollar short position against Tesla. Gates apologised for the move but Musk was still upset and became "super mean" to the Microsoft founder. /IANS