This article summarizes the information needed by paleoclimatologists, and paleoceanographers in particular, for the effective use of C37 alkenones for the estimation of past sea surface temperatures (SSTs). The structural composition of the individual alkenone compounds and their two environmental distributions are both described, as well as the main calibration equations used for the conversion of the alkenone signal into SSTs. The analytical requirements for reliable application of this paleothermometer and the geochemical aspects to be considered in the interpretation of the alkenone record are also discussed. These involve potential biases in the distribution between water column settling particles and underlying sediments, postdepositional transformation after sedimentation, and depositional asynchronies in relation to other paleoceanographic proxies, such as those derived from foraminifera. Other potential caveats, such as nonthermal physiological factors and preferential degradation of alkenones with different unsaturation are also addressed in this article. In summary, alkenone paleothermometry appears to be a robust organic geochemical tool to estimate past SST variations, if used in the appropriate paleoceanographic context.