Have you seen it in a book shop? I’d check the references section (if it has one). A lot of authors of books like this just pull stuff out of their A and are mostly sharing their own opinions and biases with you. You might even get a rant about Big Pharma and the food industry if you’re lucky. You can find all the established info on candida on a site like this without any of the filler. There haven’t been any breakthroughs in research recently, so I’m not sure what the book can add apart from spurious anecdotal evidence.