The top quark is unique among the six predicted quarks because of its large mass. That's one reason scientists persist in their enthusiastic study of this fundamental particle of nature. “If we can measure its properties precisely, we're likely to gain insight into completely new physics,” Fermilab theorist Tim Tait states in “Why We Care About the Top Quark: CDF Explains”. This and other top quark articles, Web sites and research documents are featured at the OSTI Web resource DOE R&D Accomplishments. What was the research environment one year prior to the remarkable discovery of the top quark? Find out in the 1994 DOE Report, “The Top Quark – Is it There?” Physicists at the U.S. Department of Energy Fermi National Accelerator Laboratory announced the discovery of the top quark in 1995 and continue to carry out research in high-energy physics to answer the questions: What is the universe made of? How does it work? Where did it come from? DOE R&D Accomplishments is a central forum for information about the outcomes of past DOE R&D that have had significant economic impact, have improved people's lives, or have been widely recognized as a remarkable advance in science.