Pool boiling experiments in microgravity provide some insights with phenomena not encountered in Earth gravity. Pure R-113 was used as the working fluid, with a flat heater (19 × 38 mm), consisting of a semitransparent gold film sputtered on a quartz substrate. Experiments were conducted on five space flights, with each consisting of nine different tests. Unusual nucleation and associated dynamic vapor bubble growths are reported, together with Marangoni-type convective bubble motion which contributes to the steady effectiveness of the boiling process in microgravity. Pool boiling in microgravity is compared directly with that in Earth gravity, since identical hardware was used in both circumstances.