I'm a retired faculty member. For many years I worked on radio, millimeter-wave and infrared observations of the interstellar medium in the Milky Way and other galaxies, studying star formation, molecular cloud structure, the cold ISM in elliptical galaxies, mass loss from evolved stars, and galactic structure. Starting about 1990, I worked with Jim Gunn, Robert Lupton, Michael Strauss and many others on the construction of the Sloan Digital Sky Survey, and was involved in the discovery and characterization of field brown dwarfs. Other SDSS projects included the study of magnetic variability in low-mass main sequence stars, 
low-metallicity and carbon-rich dwarf stars, and metal-rich white dwarfs. More recently I worked with direct-imaging searches for giant planets around nearby stars using AO on the Subaru telescope, first with the SEEDS survey and more recently with the CHARIS spectrograph. I've also returned to exploring the luminosity of giant carbon stars using astrometric data from Gaia.

For most of my time on the faculty, I was the department's director of graduate studies. I also established, with Scott Tremaine, its postdoctoral fellowship program and with David Spergel its summer undergraduate
research program.

With Mark Krumholz and Jenny Greene I founded and built the department's program to teach college courses in the state's prison system, now a university-wide effort, the Prison Teaching Initiative, putting in
place the algebra-calculus and statistics sequences and several laboratory science courses. I'm continuing this work with environmental science, chemistry, basic mathematics and calculus.

I got my BSc in physics from the University of Edinburgh and my Ph.D in astronomy from the University of Maryland in 1971, and was on the research staff at Caltech's Owens Valley Radio Observatory until coming
to Princeton in 1980.