The Ferber Method was created by Richard Ferber who is a Pediatrician from Boston.
You leave your baby to cry for specific amounts of time, starting at 3 minutes, before going in to quickly soothe and then leaving again. Over time you increase the length between visits until eventually your baby is able to fall asleep without you going in to soothe at all.
This method is recommended for older babies who no longer need to feed at night. The parents should also be comfortable letting their baby cry a bit.