The '''Tree of Knowledge of Good and Evil''' appears in the Book of [[Genesis]] as a key element in the [[the fall]] of man ]] from [[God]]'s [[grace]]. When God created [[Adam]] in the [[Garden of Eden]] he gave him permission to eat from any tree except that of the Tree of Knowledge.
''Genesis2:17 But of the tree of knowledge of good and evil, thou shalt not eat. For in what day soever thou shalt eat of it, thou shalt die the death. <ref>http://www.newadvent.org/bible/gen002.htm</ref>''
But Adam did eat the fruit of the tree after being induced to do so by Eve, and both of them were cast out of paradise.