Sudden Infant Death Syndrome, or SIDS, is the sudden death of an infant under one year that remains unexplained after a thorough case investigation or autopsy. Sadly, the rates of sudden infant death from suffocation have quadrupled in the past 20 years in the US, changing many families' views of cosleeping [1] and increasing awareness of the tragic syndrome. While there's no one perfect prevention technique, the American Sudden Infant Death Syndrome Institute has put together a great guide of tips for parents [2].
Check out this slideshow to educate yourself.