"You are star-stuff" was a catchy but concise phrase astronomer and television personality Carl Sagan used to illustrate our connection to the universe. All elements found on Earth today, with the exception of hydrogen and helium, originated in stars. Understanding stars and the galaxies they reside in, argued Sagan, would give us insights into our own place within the universe. · Our relationship with the cosmos, however, extends beyond the nitrogen, calcium and carbon that make up our matter. Since the beginning of time, we have relied on celestial bodies to guide our navigation, agriculture and time-keeping. The night sky has been the muse of countless artists, and influenced our religious and philosophical lives. · For 100 years, researchers in U of T's Department of Astronomy and Astrophysics have coupled superior scientific knowledge with infinite curiosity to learn more about the seemingly endless expanse of the universe. · Aided by powerful ground-based and satellite telescopes, today's observational astronomers are able to see farther than ever before. However, the advances made possible by technology have, in fact, led to even more questions on the formation of stars and planets, the creation of galaxies and the very universe itself. In this issue of Edge, we profile five observational astronomers who are seeking answers to the mysteries of our universe.