Perhaps no other medieval Jewish philosopher has been so maligned over the centuries as Gersonides. Indeed, his major philosophical work, Sefer Milhamot Ha-Shem (The Wars of the Lord, 1329), was called "Wars against the Lord" by one of his opponents. At the same time, his biblical commentaries have been highly regarded. Despite the vilification of his position, Gersonides emerges as one of the most insightful and comprehensive thinkers in the medieval Jewish tradition. He has been constantly quoted (even if only to be criticized), and, through the works of Hasdai Crescas and others, Gersonides' ideas influenced such thinkers as Gottfried Wilhelm Leibniz and Benedict de Spinoza.

Gersonides left few letters and does not talk about himself in his writings; nor is his life discussed at great length by his contemporaries. Hence, what is known of his biography is sketchy at best. Levi ben Gerson was born in 1288 in Provence...