It is likely that much of this book has been derived from Heston's own writings and from watching his TV programs, but Heston is such an interesting personality that it would be difficult for anyone to write a boring book about him.
The book has some amusing typographical errors; "sanitary" rather than "salutary" (unless this was a very poor attempt at a joke), "pallets" instead of "palates", and "foul" which are plucked. The Oxford English dictionary lists 7 alternative spellings of "cockatrice", so this book is inventive in adding "cockentrice" to that list.
It seems odd that references to "early reviews" should mention one published in 2006 (this can't have been "early", so was the date misprinted?). There were occasional references to names and facts with no explanation, and at times I reread the earlier pages, assuming that I hadn't been paying proper attention, but I found nothing. Presumably the author knew what he meant.