I'd say the general credibility of one of the authors is roughly at zero:

https://en.wikipedia.org/wiki/Matt_Ridley

'Matthew White Ridley, 5th Viscount Ridley (born 7 February 1958[1][3]), commonly known as Matt Ridley, is a British science writer, journalist and businessman. He is known for his writings on science, the environment and economics,[5] and has been a regular contributor to The Times newspaper. Ridley was chairman of the UK bank Northern Rock from 2004 to 2007, during which period it experienced the first run on a British bank in 130 years. He resigned, and the bank was bailed out by the UK government; this led to its nationalisation.[6] Ridley is a libertarian,[7] and a staunch supporter of Brexit.[8] He inherited the viscountcy in February 2012 and was a Conservative hereditary peer from February 2013, with an elected seat in the House of Lords,[9][10][11] until his retirement in December 2021.[12]'

However, doesn't mean the argument laid out in the book is wrong. Sounds like they're arguing the case for a lab leak origin, which afaik has quite a lot going for it nowadays.

cheers,
I