Half a Brain is Enough: The Story of Nico
Antonio M. Battro
Cambridge Uni. Press
134 pp.; $23

Listening in the Silence, Seeing in the Dark: Reconstructing Life after Brain Injury Ruthann Knechel Johansen
Univ. Of California Press
246 pp.; $24.95

Most of us experience our "self" as a stable property of our psyche, an identity that links our past to our present and can be projected into the future. It belongs to us, it is us—distinctive, inviolable, and enduring. Those who have experienced brain injury, malformation, or disease have learned otherwise. Their often agonizing journeys have revealed that the "self" can be shattered, altered beyond recognition, and—sometimes—reconstructed. These experiences have profound implications for our understanding of the nature of the self.

The observation that the self appears to be vulnerable to material injury or pathology challenges those who view the self as an immaterial entity enduring through time, experience, and beyond death. Some conclude that the self is simply the subjective manifestation of the organization and activities of the brain, and has no reality beyond this complex biological system. Others believe that the self is something richer and multidimensional, emerging from the relationships and interactions of a body-brain with the physical and social worlds.

These books tell the stories of two boys: Erik, 15, and Nico, five. Erik was a normal, intelligent boy until he suffered severe and extensive brain trauma in a car accident. At the time—1985—his prognosis was poor: even if he recovered from the initial coma, he was not expected to function as a fully self-aware, relational, and independent person.

Nico was born with some left-side paralysis. At two he began to experience ...