More than a century ago, the Carnegie Institution for Science was founded to provide exceptional researchers with the resources to take intellectual risks and pursue knowledge at the forefront of discovery. The scientists who were the first beneficiaries of Andrew Carnegie’s vision would not recognize the universe that we know today—a cosmos made up primarily of dark matter and dark energy. They would be equally astounded by our increasingly nuanced understanding of life down to the molecular scale. Nevertheless, after decades of transformative discovery, those first Carnegie researchers would immediately recognize the fundamental principles that guide our work today. The wide-ranging work featured in this issue of Carnegie Science demonstrates the continuing power of our first principles to inspire and support collaborative, cross- disciplinary, potentially world-changing research. In an ambitious attempt to map and monitor the world’s coral reefs, Carnegie’s Reefscape Project has forged a powerful new collaboration with Paul G. Allen Philanthropies, Planet Labs Inc., University of Queensland, and the Hawai’i Institute of Marine Biology. This effort, which relies on high-resolution satellite imagery and will use artificial intelligence, will help us to monitor changes in global reef health in real time, with the goal of finding ways to preserve these fragile, crucial ecosystems. As we work to understand and protect this planet’s ecological systems, we also are training new generations of scientists to lead this effort in the future. We are very proud to showcase important new climate research led by former Carnegie postdoctoral fellow Summer Praetorius, who is now with the U.S. Geological Survey (USGS). The exceptional work of our postdocs is central to the Carnegie Institution’s international reputation. Looking even further ahead, Carnegie is working to bring the excitement of scientific exploration to schoolchildren through the prize-winning BioEYES program, cocreated by Carnegie Department of Embryology scientist Steven Farber. In this program, elementary and high school students gain new insights into genetics and biology by studying the development of live zebrafish from single cells to free-swimming larvae. This issue also highlights Carnegie’s continuing eminence in astronomy and our scientists’ ability to wield scientific instruments, and the data they generate, to explore the universe. Carnegie postdoctoral fellow Jaehan Bae was part of an international team that took a new look at archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), an installation of 66 radio telescopes in the Atacama Desert of northern Chile, to find evidence of “baby planets” in the giant rotating disc of gas and dust surrounding a newly formed star. By studying the swirls and eddies inside the gaseous disc, they pinpointed the locations of two planets roughly the size of Jupiter—perhaps the youngest exoplanets ever detected. As I read this issue, I was impressed once again by the talent and creativity of Carnegie researchers, and by the ways in which our unique organizational structure makes it possible for us to stay nimble as we pursue exciting investigative pathways. As we move forward together, I know that the extraordinary people of the Carnegie Institution will continue to fulfill our responsibility to conduct the best science, at the highest level, and to make sure that our doors remain open to everyone who has a compelling new idea and the skill to pursue it. L E T T E R F R O M T H E P R E S I D E N T Carnegie Institution For ScienCe 1530 P Street, NW Washington, D.C. 20005-1910 202.387.6400 President Eric D. Isaacs ..... Science Deputy Margaret Moerchen ..... Director, Department of Embryology Yixian Zheng ..... Director, Geophysical Laboratory Michael Walter ..... Acting Director, Department of Global Ecology Joe Berry ..... Director, The Observatories Crawford H. Greenewalt Chair John Mulchaey ..... Acting Director, Department of Plant Biology Zhiyong Wang ..... Director, Department of Terrestrial Magnetism Richard Carlson ..... Chief Operating Officer Timothy Doyle ..... Chief Development Officer Ann McElwain ..... Editor Tina McDowell ..... Science Writer Natasha Metzler Eric D. Isaacs President Intellectual courage. Unfettered curiosity. Scholarly independence.