From the Toddler Whisperer article in the NY Times
If there is such a person as a “baby whisperer,” it is the pediatrician Dr. Harvey Karp, whose uncanny ability to quiet crying babies became the best-selling book “The Happiest Baby on the Block.”
Now Dr. Karp, assistant professor of pediatrics at the University of California, Los Angeles, has turned his attention to the toddler years, that explosive period of development when children learn language, motor skills and problem solving, among other things. The rapid pace at which all these changes occur is nothing short of astonishing, but it can also be overwhelming to little brains. A wailing baby is nothing compared with the defiant behavior and tantrums common among toddlers.

