Here it link
Note that it was last updated on May 19, 2006. Here's a quote:
"For prolonged use, place your iBook, PowerBook, MacBook or MacBook Pro on a flat stable surface. Do not leave the bottom of the computer in contact with your lap or any surface of your body for extended periods. Prolonged contact with your body could cause discomfort and potentially a burn."
Note that it was last updated on May 19, 2006. Here's a quote:
"For prolonged use, place your iBook, PowerBook, MacBook or MacBook Pro on a flat stable surface. Do not leave the bottom of the computer in contact with your lap or any surface of your body for extended periods. Prolonged contact with your body could cause discomfort and potentially a burn."