Although evidence for geomagnetic polarity reversal can be traced to the work of Brunhes (1906), it was during the 1960s that efforts got fully underway to resolve the time sequence of polarity reversals (the so-called geomagnetic polarity timescale or GPTS) from both volcanic rocks and sediments. The importance of the GPTS to the geosciences became apparent when it was realized, in the early 1960s, that polarity records in oceanic magnetic anomalies and in sedimentary sequences could be used as a powerful means of correlation and, hence, dating. Early in the process of GPTS construction (and its correlation to geologic and absolute ages), brief polarity excursions began to emerge from volcanic and sedimentary paleomagnetic records. These were often characterized by magnetization directions transitional between the two polarity states, that did not correlate to polarity intervals elsewhere, and could be attributed to high amplitude secular variation or, alternatively, to artifacts of sampling, remagnetization, and sedimentological processes. The brief (few kiloyears) duration of polarity excursions means that their recording is often fortuitous and, until recently, no single excursion was unequivocally recorded at more than one location. The uncertainty in correlation of excursions has been a result of poorly constrained excursion ages in both volcanics and sediments. As aberrant magnetization directions can be attributed to a myriad of nongeomagnetic causes, records of excursions were generally treated with skepticism. The change in attitude toward excursions began about 15 years ago and can be attributed to two important developments: (1) Improved age control in young volcanic rocks and sediments allowed coeval excursions recorded in the two media to be unequivocally correlated. (2) The development of the hydraulic piston corer by the Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP), along with enhanced penetration from other more conventional piston coring devices, such as the CALYPSO corer on board of the Research Vessel Marion Dufresne of the French Polar Institute (IPEV), led to the recovery of long sequences of high-sedimentation-rate sediments from the deep sea, that enhanced the likelihood of recording brief polarity excursions. Although the subject of polarity excursions can now be considered relatively mature compared to the situation just 15 years ago, records of polarity excursions are largely restricted to the last 2 My. We can be confident in the existence of at least seven polarity excursions in the Brunhes Chron, and perhaps as many as 11 in the Matuyama Chron. Prior to the Matuyama Chron, records of polarity excursions are rare, apart from an interval in the Middle–Late Miocene where nine excursions (or brief microchrons) are recorded at more than one location, and another four are recorded at a single location. The Brunhes and Matuyama Chrons (or the Middle–Late Miocene interval) are unlikely to be intrinsically different from other polarity chrons; therefore, we may conclude that the documentation of polarity excursions is in its infancy. Progress will require access to volcanic or sedimentary sequences that have sufficiently high eruption/sedimentation rates to facilitate recording of brief polarity excursions. The (few) polarity excursions that appear to be more or less adequately recorded are manifest as paired polarity reversals with intervening directions that define a distinct, but brief, interval of opposite polarity relative to the polarity either side of the excursion. For the best-documented excursions, such as the Laschamp and Iceland Basin excursions, the directional changes appear to be manifest globally, and there is no clear evidence that excursions can be locally manifest. Although excursional records are often characterized by transitional magnetization directions without establishment of the opposite polarity, these excursional records may represent inadequate or incomplete recording of the polarity excursion, rather than pristine records of high amplitude secular variation. The smearing of the paleomagnetic record, by the detrital remanence (DRM) acquisition process, is likely to influence all sedimentary excursional records, and to be more severe in sediments with low accumulation rates. It is now well established that polarity excursions correlate with minima in sedimentary relative paleointensity records. In the future, we expect the catalog of excursions to expand considerably, as relative paleointensity minima are increasingly associated with excursional magnetization directions. Polarity excursions combined with sedimentary paleointensity records have great potential for high-resolution stratigraphic correlation. One of the major challenges in the study of abrupt climate change is the quest for a means of correlation of high-resolution climate records at an appropriate resolution that is not easily achieved using standard marine isotopic methods. The study of polarity excursions is, therefore, not only relevant to understanding geomagnetic field behavior and for constraining numerical simulation of the geodynamo, but is also important for paleoceanographic and paleoclimatic studies that require precise, millennial-scale, stratigraphic correlation.