Four originals, one magazine reprint: the first story collection centered on McCaffrey's immensely popular Dragonriders and their battle to keep planet Pern free of the invidious, corrosive Thread. As the title implies, the stories form a sort of chronology of the early days of Pern's colonization. The original survey and exploration team designate the planet as P.E.R.N.: parallel Earth, resources negligible. After colonization, the Southern Continent must be evacuated following a volcanic eruption, the colonists in their fragile ships aided by intelligent, talking dolphins. Famed Ruatha Hold is founded by big, genial Irishman Red Hanrahan. Later, after resounding success in destroying Thread before it can fall to ground, the Dragonriders expand into a second, then a third Weyr. Finally, a remnant of the original colonists, cut off from the Dragonrider groups, are rescued by a Federation vessel before the Pern system and its cometary cloud, permeated with deadly Thread organisms, is interdicted, and so cut off from the rest of humanity. Fairly mediocre stories, overall, but don't underestimate the crowd-pulling power of McCaffrey's all-but-legendary planet.