The book claims that Admiral Zheng He and his fleet of ships sailed west from China through Indonesia, around Africa, and across the Atlantic to South America, decades before Columbus made his famous voyage. It's a very interesting read, but it's making some pretty bold claims that I'm not quite sure I believe.
It's not accurate and he's not well regarded. Menzies makes a lot of claims that aren't supported by any evidence. There's no evidence for zheng he ever going that far in any records, Chinese or otherwise. I don't know any historians that take him at all seriously.
I'm on mobile so I can't paste the links but do a quick search on this sub. This question gets asked from time to time and you'll be able to in answers with more specific examples.
You may be interested in this section of our FAQ.