Abstract
The 4th International Symposium on Instrumentation Science and Technology (ISIST'2006) was held in Harbin, China in August 2006. It included sessions on all aspects of the theory, design, test and application of measurement technologies and instruments. The bulk of the Symposium papers, after peer review, have been published by IOP Publishing in the Journal of Physics: Conference Series; a number of papers were selected for publication in Measurement Science and Technology and we hope that readers will find these give a valuable insight into the key topics of the conference.