Apples are the fruit of a tree of the genus Malus, which is a member of the Rose family (Rosaceae), and have been cultivated throughout recorded history. The wild ancestor of the apple was probably a tree still found in Kazakhstan, Malus sieversii (which has no common name). Researchers are working with M. sieversii, which is resistant to many diseases and pests, in order to create a hardier domestic apple.
Although the "fruit" of Genesis is not identified, the apple is mentioned in the Bible exactly ten times: in Deuteronomy, Psalms and Proverbs (originating the phrase "apple of your eye" in English); Song of Songs, Joel and Zechariah. The assumption that the fruit that Adam and Eve ate was an apple can probably be attributed to its portrayal in artistic renderings of the fall from Eden.
While there are a huge variety of different kinds of apples, the most common is M. sylvestris, which is grown commercially and is one of the most important fruits in temperate climates. It is believed to have been native to the Caucasus Mountains, originally.
Among the most common varieties of apples are the "Red Delicious", "Golden Delicious", "Winesap", "Jonathan", "Mc'Intosh", and "Gala". The "Granny Smith" is also somewhat popular, though tarter than the others; as such, it makes a good cooking apple. It is a light speckled green and looks somewhat like the "Golden Delicious"; it is the apple used in the picture for the Apple label which produces CDs by The Beatles.
See also Apple Computer.