Undergraduate physics programs tend to treat preparation for graduate school as the default, and pay relatively little attention to informing students about, and preparing them for, other careers. However, most physics graduates are employed outside of academia. With support from the NSF, the AAPT and APS formed a Joint Task Force on Undergraduate Physics Programs (JTUPP) to identify the skills and knowledge that undergraduate physics degree holders need to be well prepared for a diverse set of careers. The Task Force reviewed employment data, surveys of employers, and reports generated by other disciplines. We also met with physicists in selected industries to get their views on the strengths and weaknesses of physics graduates, commissioned a series of interviews with recent physics graduates employed in the private sector, and identified exemplary programs that ensure that all of their students are well prepared to pursue a wide range of career paths. The resulting report “PHYS21: Preparing Physics Students for 21st Century Careers” recommendations intended to help departments and professional associations support student career preparation.