Sustainability powerfully validates the liberal arts. In response to contemporary accusations of economic impracticality, defenders of liberal education have emphasized how such skills as critical thinking and "learning to learn" are vital to success in careers. This approach readily extends to sustainability, which has become a growing source of employment across many fields, including business and finance. Experts in careers related to sustainability particularly require the ability to constantly remake their technical training in an arena in which successful strategies must be flexible and adaptive. Sustainability's validation of the liberal arts extends beyond economics. While liberal education can hold its own in a contemporary dialogue dominated by concern over jobs and "return on investment," its origins and ultimate worth center on citizenship. The degree of commitment to sustainability education and how it is realized will vary by institution. For a few, education for sustainability (EfS) will become the organizing principle for general education or indeed the entire liberal arts curriculum. Most will likely view it as a dimension of greater or lesser significance in what they do. EfS may infuse first-year seminars, majors, minors, electives, and/or other curricular options. In all cases, faculty will be key to success. Sustainability has the potential to vitalize and validate liberal learning in ways that both deepen teachers' practice and engage them meaningfully with the wider world.