My take on it: This book is organized around standard nonfiction writing themes (e.g., profiles, place, science & nature), Each section repeats the following recipe: example stories falling into two categories: personal essay and literary journalism (hence the "I & Eye" subtitle) The sections wrap up with a smattering of craft essays by authors who are well-known for writing in their corollary subject. Tracy Kidder, Phillip Lopate and Scott Russell Sanders, for example, write the craft essays ending the section labeled "Portraits".
It's a great collection. the craft essays are a great writer's resource and the essays are moving my reading in new directions; I'm finding lots of wonderful new-to-me authors here.