Um...scary book, very scary. I went out and bought a Vitamin D supplement before I was even 1/3 of the way through it. Very easily readable and grabs you like a suspense novel. Part one, the effects of Vitamin D deficiency, gets you wondering 'am I deficient?' so you read on...Part Two, how to tell if you are deficient gets you thinking (unless you work on a chain gang or live in a loincloth in the tropics)'OMG I'm deficient what do I do about it?'...part three is what to do about it. The author repeats the most important information several times throughout the book so you really, really do 'get it'
I only give 4 stars though for one reason - there are several pages of references in the back, always a good thing, but when in the text Dr Holick says 'studies have found that...' he doesn't give a connection at that point to the original reference, so if, like me, you want to read the whole study it's impossible to find the one he is referring to.