Dragonfly is NASA's most recently selected planetary science mission. Its science entails prebiotic chemistry, habitability, and a search for chemical biosignatures at the surface of Saturn's giant moon Titan. Titan's draw derives from its status as an Ocean World and from the presence of complex carbon chemistry that may trace out the pathways with which life formed on Earth 4 Gyr ago. Products of atmospheric photolysis of methane may react in either water or hydrocarbon solvents. Titan sports liquid water in its subsurface ocean today, but also transiently supports surface water in the wake of cryovolcanic eruptions and impact events leading to melting of target ice. Cassini discovered extant liquid methane/ethane seas at Titan's north pole whose potential for prebiotic chemistry remains unknown. Dragonfly will land in Titan's vast organic sand dune fields to sample both organic-rich sediments and crustal water ice. To get between the two, the entire lander is an octocopter that will achieve mobility via flight instead of with wheels as on Mars.