Sustainability is often discussed in terms of maintenance, or awareness-- engagements with the known. This issue asks a series of artists for their work and reflections on the vast expanse beyond the known-- from questions of nothingness, to existential crises, to attempts to anticipate the unexpected. How are creative practices sustained in the face of uncertain funding futures, or vast cultural shifts? How do the arts aid sustainability when change is vast, immediate, and unknown? How can we be certain that what we sustain will be useful?