James Shapiro said this quote

We've inherited many ideas about writing that emerged in the eighteenth century, especially an interest in literature as both an expression and an exploration of the self. This development — part of what distinguishes the modern from the early modern — has shaped the work of many of our most celebrated authors, whose personal experiences indelibly and visibly mark their writing. It's fair to say that the fiction and poetry of many of the finest writers of the past century or so — and I'm thinking here of Conrad, Proust, Lawrence, Joyce, Woolf, Kafka, Plath, Ellison, Lowell, Sexton, Roth, and Coetzee, to name but a few — have been deeply autobiographical. The link between the life and the work is one of the things we're curious about and look for when we pick up the latest book by a favorite author.