The Fussy Baby Book
Very simply, babies fuss for the same reasons adults fuss: they hurt either physically or emotionally, or they need something. There is a wide spectrum of types of crying. At the quieter end is the baby who fusses to be picked up but is easily comforted and satisfied as long as he is held. At the other extreme is the baby who hurts - the inconsolably crying baby who merits the label "colicky."