This books analyses of one of the most individual and highly developed genres in German literature up to the early 1960s.

There's likely no more of a thankless job in the Federation than temporal investigation. While starship explorers get to live the human adventure of traveling to other times and realities, it's up to the dedicated agents of the Federation Department of Temporal Investigations to deal with the consequences to the timestream that the rest of the Galaxy has to live with day by day. But when history as we know it could be wiped out at any moment by time warriors from the future, misused relics of ancient races, or accident-prone starships, only the most disciplined, obsessive, and unimaginative...