The Indo-Pacific lionfishes, Pterois miles and P. volitans, are now established along the Southeast U.S. and Caribbean and are expected to expand into the Gulf of Mexico and South America. Prior to this invasion little was known regarding the biology and ecology of these lionfishes. I provide a synopsis of lionfish biology and ecology including: invasion chronology, taxonomy, local abundance, reproduction, early life history and dispersal, venomology, feeding ecology, parasitology, potential impacts, and control and management. This information was collected by review of the literature and by direct field and experimental study. I confirm the existence of an unusual supraocular tentacle phenotype and suggest that the high prevalence of this phenotype in the Atlantic is not the result of selection, but likely ontogenetic change. To characterize the trophic impacts of lionfish, I report a comprehensive assessment of diet that describes lionfish as a generalist piscivore that preys on over 40 species of teleost comprising more than 20 families. Next, I use the histology of gonads to describe both oogenesis and reproductive dynamics of lionfish. Lionfish females mature at approximately 170 mm total length and reproduce several times per month throughout the entire calendar year off North Carolina and the Bahamas. To investigate predation, an important component of natural mortality, I assessed the vulnerability of juvenile lionfish to predation by native serranids. Juvenile lionfish were largely avoided as prey suggesting that predation mortality by serranids will not likely be a significant source of mortality for lionfish populations. Last, I used a stage-based, matrix population model to estimate the scale of control that would be needed to reduce an invading population of lionfish. Together, this research provides the first comprehensive assessment on lionfish biology and ecology and explains a number of life history and ecological interactions that have facilitated the unprecedented and rapid establishment of this invasive finfish. Future research is needed to understand the scale of impacts that lionfish could cause, especially in coral reef ecosystems, which are already heavily stressed. This research further demonstrates the need for lionfish control strategies and more rigorous prevention and early detection and rapid response programs for marine non-native introductions.