Book Review: Mothers on the Fast Track: How a New Generation Can Balance Family and Careers. By Mary Ann Mason and Eve Mason Ekman. New York: Oxford University Press, 2007, 176 pp. $15.95 (paper): Women at the Top: Powerful Leaders Tell Us How to Combine Work and Family. By Diane F. Halpern and Fanny M. Cheung. Malden, MA: John Wiley, 2008, 320 pp., $29.95 (cloth)