Parasites and parasitism is common. Worm macroparasites have evolved life-history traits that allow them to successfully transmit between spatially and temporally separated patches of host resource and to survive within these environments. Macroparasites have common life-history strategies to achieve this, but these general themes are modified in a myriad of ways related to the specific biology of their hosts. Parasite life histories are also dynamic, responding to conditions inside and outside of hosts, and they continue to evolve, especially in response to our attempts to control them and the harm that they cause.