In a world with access to unlimited amounts of data, how can users who need to make critical scientific and technical decisions find high quality, reliable data? Today, more than ever, the CRC Handbook of Chemistry and Physics remains a hallmark of quality. For over 100 years, the Handbook has provided property data on chemical compounds (now over 20,000) and all physical particles that have been reported in the literature, carefully reviewed by subject experts. Every year older collections are updated with the latest values and new areas will be added as science progresses.