What is ferberizing?

Ferberization is a technique invented by Dr. Richard Ferber to solve infant sleep problems. It involves "baby-training" children to self-soothe by allowing the child to cry for a predetermined amount of time before receiving external comfort.
Dr. Richard Ferber discusses and outlines a wide range of practices to teach an infant to sleep. The term ferberization is now popularly used to refer to the following techniques:
Take steps to prepare the baby to sleep. This includes night-time rituals and day-time activities.