Bill McKibben is a journalist and activist who founded the environmental organisation 350.org. The author of fifteen books, including the bestsellers The End of Nature, Eaarth and Deep Economy, he is the Schumann Distinguished Scholar in Environmental Studies at Middlebury College and the winner of the Gandhi Prize, the Thomas Merton Prize and the Right Livelihood Prize. He lives in Vermont.

N. T. Wright is the former bishop of Durham in the Church of England and one of the world's leading Bible scholars. He is now serving as the Chair of New Testament and Early Christianity at the School of Divinity at the University of St. Andrews.

For twenty years he taught New Testament studies at Cambridge, McGill, and Oxford Universities, and he has been featured on ABC News, Dateline, The Colbert Report, and Fresh Air. Wright is the award-winning author of Surprised by Scripture, The Case for the Psalms, How God Became King, Simply Jesus, After You Believe, Surprised by Hope, Simply Christian, Scripture and the Authority of God, The Meaning of Jesus (coauthored with Marcus Borg), as well as being the translator for The Kingdom New Testament.

Elizabeth Lev is an art historian living in Rome, where she teaches Baroque and Renaissance Art.

'A farmer of sorts and an artist of sorts,' Wendell Berry is the author of more than fifty books of poetry, fiction, and essays.

He has received fellowships from the Guggenheim, Lannan, and Rockefeller foundations and the National Endowment for the Arts, and also the Dayton Literary Peace Prize, the Cleanth Brooks Medal for Lifetime Achievement, and the National Humanities Medal.

For more than forty years, he has lived and farmed in his native Henry Country, Kentucky, with his wife, Tanya, and their children and grandchildren.

Barbara Kingsolver is one of the most important voices of our time. Barbara Kingsolver’s previous fourteen works of fiction and non-fiction have been translated into dozens of languages and earned a devoted readership.

She won the Orange Prize in 2010 for The Lacuna and her novel Flight Behaviour was shortlisted for the Women’s Prize for Fiction.

In 2000 she was awarded the National Humanities Medal, her country's highest honour for service through the arts. Before she made her living as a writer, Kingsolver earned degrees in biology and worked as a scientist. She now lives with her family on a farm in southern Appalachia.

John Muir (1838–1914) ranks among America's most important and influential naturalists and nature writers.

Devoted to the preservation of wilderness areas, Muir founded the Sierra Club and was active in the establishment of Yosemite National Park.