The XIX International Conference on Laser Spectroscopy, one of the leading conferences in the very diverse and still growing field of laser spectroscopy, was held in Hokkaido, Japan, on June 7-12, 2009. This volume, comprising a collection of invited contributions presented at the conference, will report on the latest developments in the area of laser spectroscopy and related fields: cold atoms and molecules, degenerate quantum gases, quantum optics, quantum information processing, precision measurements, atomic clock, ultra-fast lasers and strong field phenomena, and novel spectroscopic applications.

The XV International Conference on Laser Spectroscopy brought together spectroscopists from all over the world working in the very diverse and still growing field of laser spectroscopy. It addressed a large number of modern scientific issues at the highest level.

This is the latest volume in the series of proceedings from the biannual International Conference on Laser Spectroscopy, one of the leading conferences in the field. Over its 34-year history, this conference series has been a forum for the announcement of many new developments in laser physics and laser spectroscopy and more recently laser cooling of atoms and quantum information processing. The proceedings include contributions from the invited speakers and a selection of contributed papers.A particular theme for this volume is precision measurements. Motivated by the untapped potential for vast improvements in accuracy offered by atomic systems, this subject has advanced tremendously in recent years by new developments in laser technology. This has been recognized by the 2005 Nobel Prize in Physics awarded to two of the pioneers in the field and contributors to these proceedings, J L Hall and T W Hänsch.The other main theme of the proceedings is cold atoms and quantum degenerate gases. This conference marked the 10th anniversary of the first announcement of an atomic Bose-Einstein Condensate at the 12th International Conference on Laser Spectroscopy with a contribution from Nobel Laureate Eric Cornell.