Joshua Wolf Shenk is the author of 2005’s Lincoln’s Melancholy: How Depression Challenged a President and Fueled His Greatness and can discuss the 16th president’s possible depression and how it may have fed his spirituality. He lives in Brooklyn, N.Y.

Harold Holzer is senior vice president of external affairs for the Metropolitan Museum of Art in New York City. He is also co-chairman of the Abraham Lincoln Bicentennial Commission and a member of its speakers bureau. Among the lectures he offers is “Lincoln and the Jews.” He has written several books on Lincoln.

David Grubin is producer and director of the PBS television special Abraham and Mary Lincoln: A House Divided, which aired as part of American Experience and included discussions of Lincoln’s faith.

Eric Foner is a history professor at Columbia University in New York City and author of A House Divided: America in the Age of Lincoln.

Michael Croland is the writer behind heeb’n’vegan, a blog about Jewish veganism.

Rynn Berry is the author of Food for the Gods: Vegetarianism & the World’s Religions and an adviser to the North American Vegetarian Society. He is based in New York City.

The Society of Ethical and Religious Vegetarians promotes a plant-based diet in the belief that vegetarianism is consistent with religious teachings. Its pamphlet on vegetarianism and world religions traces support for a plant-based diet in religious scriptures and teachings. Stephen Kaufman is coordinator.

All-creatures.org promotes veganism, vegetarianism and a “cruelty-free lifestyle” based on Judeo-Christian teachings and ethics. It is run by the Mary T. and Frank L. Hoffman Family Foundation and is based in Athens, N.Y.

The Jew and the Carrot is a blog by The Jewish Daily Forward for Jews interested in sustainability and the politics of food. It maintains a list of contributing writers.