<p>Fracture mechanics, originating from Griffith’s pioneering theory, has evolved into a foundational framework for understanding and predicting material failure across scales. Over the past century, it has expanded from linear elasticity to encompass nonlinear, dynamic, and stochastic behaviors—capturing fracture, fatigue, rupture, damage, and fragmentation in materials ranging from metals and ceramics to polymers, composites, soft matter, and biological tissues. Despite these advances, the field is far from complete. As modern materials and structures operate under unprecedented extremes of size, rate, and environment, classical assumptions—continuum validity, small-scale yielding, and singular field dominance—are increasingly challenged.</p><p> This Perspective identifies 25 outstanding issues that delineate the current and emerging frontiers of fracture mechanics. Organized across three interrelated domains—theoretical foundations, material behavior, and engineering applications—these issues span the limits of continuum theory, attainable fracture toughness, multiscale crack coalescence, fracture under extreme environments, and the integration of artificial intelligence for data-driven modeling. Collectively, they highlight a paradigm shift toward multiscale, multiphysics, and information-rich approaches that bridge atomistic processes and macroscopic failure. Far from a mature or closed discipline, fracture mechanics remains an evolving science—one that will continue to play a central role in designing materials and structures with unprecedented strength, toughness, and resilience in the century ahead.</p>