W1 and W2 Theories, and Their Variants: Thermochemistry in the kJ/mol   Accuracy Range
  In this 2nd chapter of the book Quantum Mechanical Prediction of Thermochemical Data" (ed. Jerzy Cioslowski, Kluwer, 2001; ISBN 0-7923-7077-5), we review the nonempirical computational thermochemistry methods W1 and W2 theory and their variants. The chapter is made available online following a change in publisher E-print policy. 
Jan M.L. Martin and S. Parthiban