This book constitutes the thoroughly refereed post-proceedings of the 4th International Workshop on Approximation and Online Algorithms, WAOA 2006, held in Zurich, Switzerland in September 2006 as part of the ALGO 2006 conference event. The 26 revised full papers presented were carefully reviewed and selected from 62 submissions.

This book constitutes the thoroughly refereed post-proceedings of the 4th International Workshop on Approximation and Online Algorithms, WAOA 2006, held in Zurich, Switzerland in September 2006 as part of the ALGO 2006 conference event. The 26 revised full papers presented were carefully reviewed and selected from 62 submissions.

This book constitutes the thoroughly refereed post-proceedings of the 4th International Workshop on Approximation and Online Algorithms, WAOA 2006, held in Zurich, Switzerland in September 2006 as part of the ALGO 2006 conference event. The 26 revised full papers presented were carefully reviewed and selected from 62 submissions.