On that subject, an absolutely must-read book is "Hard To Be God" (by Strugatsky; http://en.wikipedia.org/wiki/Hard_to_Be_a_God http://en.wikipedia.org/wiki/Har

On that subject, an absolutely must-read book is "Hard To Be God" (by Strugatsky; http://en.wikipedia.org/wiki/Hard_to_Be_a_God http://en.wikipedia.org/wiki/Hard_to_Be_a_God ), an absolutely brilliant meditation on the whole Prime Directive issue (basic thesis: it's harder to bring in positive influence than it seems, thus the title)