Antarctica is renowned for its extreme cold; yet surprisingly, radar measurements have revealed a vast network of lakes, rivers, and streams several kilometers beneath the Antarctic ice sheet. Sealed from Earth's atmosphere for millions of years, they may provide vital information about microbial evolution, the past climate of the Antarctic, and the formation of ice sheets, among other things. The next stage of exploration requires direct sampling of these aquatic systems. However, if sampling is not done cautiously, the environmental integrity and scientific value of these environments could be compromised. At the request of the National Science Foundation, this National Research Council assesses what is needed to responsibly explore subglacial lakes. Exploration of Antarctic Subglacial Aquatic Environments concludes that it is time for research on subglacial lakes to begin, and this research should be guided by internationally agreed upon protocols. The book suggests an initial protocol, which includes full characterization of the lakes by remote sensing, and minimum standards for biological and other types of contamination.