The University of Wisconsin-Madison Department of Astronomy and the Astrophysics group in the Department of Physics have been hosting a Research Experiences for Undergraduates (REU) program in Astronomy and Astrophysics for the past twenty years. During the summer of 2023, a minimum of eight students will work in Madison with faculty and research scientists in these departments for ten weeks. The program main objective is to provide students with high-quality research projects, experienced mentors, and a supportive research atmosphere. Student projects cover a broad range of scientific areas, with a new focus on the origins of life in the Universe (NSF’s ”Understanding the Rules of Life”) and multi-messenger astrophysics (”Windows on the Universe”), both supported by a recent cluster-hi