The taphonomic state of ichnofossil assemblages can be measured using two independent parameters: (1) completeness of the preserved record of biogenic activity that occurred in a substrate (ichnologic fidelity); and (2) degree of manifestation of the trace fossils that are preserved (trace fossil visibility). These parameters are controlled by environmental dynamics, tracemaker behavior and position in substrates, and a range of diagenetic processes (mechanical compaction, selective mineralization, lithification, and weathering). Consequently, trace fossil preservational modes can be exploited in studies of depositional regimes, paleobiology, and post-depositional histories. Trace fossil assemblages characterized by relatively high ichnologic fidelity, trace fossil visibility, or both may be particularly informative and, hence, can be considered as ichnofossil-lagerstätten.