In 1990, HBO adapted William Prochnau's 1983 novel "Trinity's Child" for a TV movie that served as a reminder of just how quickly the world can descend into nuclear chaos. There's nothing more indicative of the way in which the concept of nuclear destruction became almost banal during the Cold War than the term "nuclear exchange." For many, the infamously disturbing TV movie "Threads" remains the most memorable example. Then, there's Prochnau's "Trinity's Child," which similarly dramatized a rapid descent into nuclear war. Like Burdick's book, "Trinity's Child" was adapted for the screen as "By Dawn's Early Light," an HBO original movie that aired one year after the fall of the Berlin Wall in 1990.