It comes in many sizes and colors, and even the shape varies considerably. The etrog is undoubtedly one of the world's most remarkable fruits, whose only use is as one of the "four species" (arba minim) on Sukkot. Rabbi Dunner delves into the history of the etrog, and particularly into the modern controversy over hybridized etrogim. A modern scientific study offers a fascinating revelation that ties in with a famous passage in the Talmud.