The sleep advice given by "Baby Wise" is similar to Richard Ferber's advice given in his popular book "Solve Your Child's Sleep Problems". The Ferber method of getting a baby to sleep similarly includes putting the baby to bed when awake The baby is expected to learn how to fall asleep alone. Both methods warn the parents against using aids such as a pacifier to ease the baby into sleep, and both methods describe putting the infant to sleep without rocking, cuddling or nursing applied for the sole purpose of putting child to sleep. "Crying it out" is expected from the infant during the early training periods, until about eight weeks of age.