We all encounter failure in our professional lives: failed projects, failed systems, failed organizations. We often think of failure as a negative, but it has intrinsic value -- and since it's inevitable that we'll eventually experience failure ourselves, it's important to know how to accept it, how to take lessons from it, and how to grow from it professionally. Fail4Lib, now in its 5th year, is the perennial Code4Lib preconference dedicated to discussing and coming to terms with the failures that we all face in our professional lives. It is a safe space for us to explore failure, to talk about our own experiences with failure, and to encourage enlightened risk taking. The goal of Fail4Lib is for participants to be adept at failing gracefully, so that when we do fail, we do so in a way that moves us forward. This half-day preconference will consist of case studies, round-table discussions, and, for those interested in sharing, lightning talks on failures we've dealt with in our own work.