This article is a critical review of David Boonin's book, A Defense of Abortion (Cambridge University Press, 2002), a significant contribution to the literature on this subject and arguably the most important monograph on abortion published in the past twenty years. Boonin's defense of abortion consists almost exclusively of sophisticated critiques of a wide variety of pro-life arguments, including ones that are rarely defended by pro-life advocates. This article offers a brief presentation of the book's contents with extended assessments of (...) those arguments of Boonin's that are his unique contributions to the abortion debate and with which the author disagrees: (1) Boonin's critique of the conception criterion and his defense of organized cortical brain activity as the acquired property that imparts to the fetus a right to life: (2) Boonin's defense of J. J. Thomson's violinist argument and his distinction between responsibility for existence and responsibility for neediness and its application to pregnancy. (shrink)