Karl Theodor Jaspers (February 23, 1883 – February 26, 1969) was a German psychiatrist and philosopher who had a strong influence on modern seen as one of the founders of Existence Philosophy through his own work and through the rediscovery of Kierkegaard.
There are a good many of his works now in PDF format on the Web making it much easier to find and read one of the least appreciated but most insightful thinkers in the last century.
Try the Internet Archive for a quick overview of PDF's and discussions available at just one location.
"Philosophy, the goal of true community among men who are themselves, has been wrought by lonely, distant individuals. In an extravagance of agonies and certainties, they sent us word but did not bid us follow. The experience they show us was singular and unrepeatable. They were sacrificial victims, so to speak, whose visions--translated into thought-- convey to us what a less hazardous fate could not have brought to light. In our philosophizing we revere what they proved humanly possible. We want to catch their every word; they have made it impossible for us to take any knowable order for the only true one.
"But we ourselves philosophize in communication, not in isolation. Our point of departure is man's relation to man, the individual's way of dealing with the individual. In our world, linked fellowship seems like the true reality. Communication leads to our brightest moments and lends weight to our life. My philosophizing owes its every content to people who have come close to me. I consider it true in so far as it aids communication. Man cannot place himself above man; he can approach only those he meets on the same level. He cannot teach them what to do, but together they can find out what they want and what they are. There can be solidarity in what must animate our existence if it is to turn into being. (Philosophy I, 1932, 2)