The essays were all written from 1979 to 1996 (hence the title Starting Point: 1979 – 1996), the period within which Miyazaki directed Lupin III: Castle of Cagliostro, Nausicaa of the Valley of the Wind, Laputa, Totoro, Kiki's Delivery Service, and Porco Rosso.
VIZ is releasing the book, and it's just come up for preorder-- the book will come out July 7 (I wonder if there'll be some early copies at Anime Expo?). Ghibli World also has an interview with the book's editor, Nick Mamatas.
I love the cover illustration. Definitely, definitely buying this.