This book is an analysis of scientific literature, and the authors pedigrees seem convincing to me:
https://en.wikipedia.org/wiki/Chernobyl:_Consequences_of_the...Most authors of negative critics are authors of reports this book criticized, and other ones are weirdos. The book's authors answered to all critics.
One of the critics is Monty Charles. His own work, done for the UNSCEAR (a pro-nuke UN agency) in 2006, is heavily criticized in the book. He then criticized this book.
Another critic was published by Mona Dreicer, who worked for the International Atomic Energy Agency (IAEA) (another UN pro-nuke agency) and the book criticized her work.
Another one is M. Balonov, long-time contributor of reports published by UN-agencies, and the book criticizes his work.
S. Jargin, another author of a negative review, sees flaws in each and every publication criticizing a powerful industry. For example asbestos is in his opinion not a concern and its use unduly prohibited ( https://www.researchgate.net/publication/321527973_Asbestos_... )
His 'debate' with Rosamund Katz and Janette Sherman is surrealistic.
https://www.researchgate.net/publication/278732482_Who_Is_Af...
The UN is notoriously pro-nuke, and the UNSCEAR only composed of nuclear-energy related nations (exploiting reactors, extracting uranium...). About the WHO: http://independentwho.org/