According to your review of Iain McGilchrist’s The Master and His Emissary: The Divided Brain and the Making of the Western World (New Haven, Connecticut: Yale University Press, 2009), his main claim is that the brain’s left hemisphere, or the Emissary in the title, has wrested control from the right, or the Master (“Right and Left,” November 28, 2009). The left’s world is narcissistic, and its main motivation is power, whereas the right’s world is suffused with ideals that are egalitarian and communitarian in nature. Over the centuries, the upstart has created a dehumanized society, caused environmental despoliation, and fashioned willfully ugly modern art and music. As you conclude your review, McGilchrist brings his book to a close with a “deflating admission” that his main claims about the cerebral hemispheres have the ring of loose analogies rather than hard explanations. Indeed. But you fail to point out that the author’s admission puts a dent in his own argument: the Master wrests control back from the Emissary in the nick of time. Of course, the sharp division of the hemispheres is nothing but an entertaining metaphor.