AWOL on the Appalachian Trail
David "AWOL" Miller decided to quit his computer job in Florida to hike the AT. With the support of his wife and 2 children he set out for Maine. The book is an account of his hike and the struggles a thru hiker goes through. It's also a great peak into the day to day life of a long distance hiker. Like many hikers, AWOL found a way to stay connected to the AT. He now publishes the yearly guidebook that most hikers use (including me)!
A Walk in the Woods
Forget, the movie. It was terrible. The book is part journal and part history book. It's also attributed for starting the public interest in the AT which has generated record numbers of hikers. It's hilarious and informative.
Grandma Gatewood's Walk
Emma Gatewood survived domestic abuse and learned about the AT from a magazine in her dentist's office. Once her kids were grown, she left Ohio with some Keds and a duffel bag slung over her shoulder and made her way to Georgia before hiking the AT in its entirety was a thing. It's an inspirational story.
Appalachian Trials
This book deals with the psychological aspect of a long hike. Having never backpacked in his life, Zach hiked the AT in 4 months. Several chapters are good reads for family members not hiking. Zach also went on to create a very popular website that hosts journals, gear reviews, and other information for a prospective thru hiker.
Here's a great link to his site that answers many of the common questions a hiker asks:
http://appalachiantrials.com/how-to-thru-hike-appalachian-trail-101-guide/
Here's an interactive map:
http://appalachiantrials.com/appalachian-trail-thru-hiker-resources-2/appalachian-trail-interactive-map/