Enchanted Hunters: the Power of Stories in Childhood by Maria Tatar
Although, as Byatt says, the book is 'not about classic fairytales but about authored children's writing' there are mentions of Andersen and the Grimms, as well as Peter Pan and The Wizard of Oz - which are often considered to be fairy tale like - alongside many other important children's classics. This is a study of 'what children take and need from stories, and how this is not always what parents imagine'.
'This is a grown-up book for grown-up people who haven't forgotten being childhood readers. It satisfies imagination and curiosity, revisiting things you suddenly remember clearly, telling you new things you didn't know.'
I can't wait to read the book, and what a treat to read a review of Tatar by Byatt!