Cover: Poly(ethylene glycol) hydrogels embedded with gradients play a critical role in directing cell behavior and tissue regeneration. Perfusion based frontal photopolymerization is used to create scaffolds with tunable gradients. The influence of polymerization conditions on the speed of the hydrogel front as well as on gradients in hydrogel swelling are reported. Further details can be found in the article by M. V. Turturro, D. M. V. Rendón, F. Teymour, and G. Papavasiliou* on page 107.