The emergence of sequence stratigraphy—the study of genetically related facies within a framework of chronostratigraphically significant surfaces—triggered a conceptual breakthrough in stratigraphy (Van Wagoner et al., 1990; Baum and Vail, 1998) and vastly improved our understanding of the fossil record (Holland, 1999). Sequence-bounding unconformities and transgressive surfaces are the record of relative sea-level changes and a signature of time intervals not represented in the geological record. This is a key issue for those interested in documenting the steps in the history of life. Despite a good sampling of the rock record (Donovan and Paul, 1998), concern that the sedimentary record is biased remains widely justified by recent studies (Smith, 2001; Crampton et al., 2003). Rock biases and sedimentary gaps strongly determine what we perceive as abundance and diversity patterns (Raup, 1972; Smith, 2001; Peters, 2005). Sequence stratigraphic architectures, however, also allow the role of sea-level changes to be tested as a driving force of ecology and evolution in the marine realm. Sea-level variations as sources of minor and major environmental perturbations (Hallam and Wignall, 1999) are factors in ecosystem structure (Olszewski and Erwin, 2004) and macroevolution (Peters, 2006). A session of the 2004 American Association of Petroleum Geologists Dallas Meeting entitled, “Sea-level change, climate variation, and the restructuring of shallow marine communities,” addressed paleobiological factors related to this important aspect of sequence stratigraphy. Some participants of that session and other researchers have contributed their thoughts on the subject in this special issue of PALAIOS. Before sequence stratigraphic concepts made their way into paleontologic practice, authors studying the biotic effects of relative sea-level change used formations as the natural subdivisions of the rock record and derived sea-level templates from 106–107-year duration transgressive-regressive cycles (e.g., Rollins et al., 1979; Jablonski, 1980; Hallam, …