Statistics and Computing Series Editors: J. Chambers D. Hand W. Ha¨rdle Leland Wilkinson The Grammar of Graphics Second Edition With 410 Illustrations, 319 in Full Color With contributions by Graham Wills, Dan Rope, Andrew Norton, and Roger Dubbs Leland Wilkinson SPSS Inc. 233 S. Wacker Drive Chicago, IL 60606-6307 USA leland@spss.com Series Editors: J. Chambers Bell Labs, Lucent Technologies 600