Abstract
Terahertz irradiation and sensing is being applied for the first time to a wide range of fields outside the traditional niches of space science, molecular line spectroscopy and plasma diagnostics. This short summary serves as an introduction to a special focused session of the IEEE IMS 2004 and surveys some of the terahertz measurements and applications of interest in the biology and medical sciences. A more complete paper has been submitted to the special issue of MTT Transactions.