Traditionally, the human soul is regarded as a nonphysical concept that can only be examined by psychiatrists and theologists. In his new book, <I>The Astonishing Hypothesis,</I> Nobel Laureate Francis Crick boldly straddles the line between science and spirituality by examining the soul from the standpoint of a modern scientist, basing the soul's existence and function on an in-depth examination of how the human brain "sees."