Short answers, pulled from the story.
Karl Jaspers is best known for his 1913 work General Psychopathology, which argued that psychiatrists should diagnose mental illness by the form of symptoms rather than their content. He also introduced the distinction between primary and secondary delusions, and developed the biographical method of studying patients in close individual detail.
Jaspers defined primary delusions as autochthonous, meaning they arise without apparent cause and are incomprehensible in terms of normal mental processes. Secondary delusions, by contrast, are shaped by the patient's background, current situation, or mental state.
Jaspers was forced to retire from teaching in 1937 because the Nazi regime classified him as having a "Jewish taint" (jüdische Versippung) due to his marriage to his Jewish wife, Gertrud Mayer. A publication ban was added in 1938, and the two of them lived under threat of deportation until American troops occupied Heidelberg on the 30th of March 1945.
In his three-volume Philosophy (1932), Jaspers argued that rational inquiry reaches a limit at which individuals must either despair or make a leap of faith toward Transcendence, which he described as that which exists beyond time and space. Making that leap brings individuals into confrontation with their own unlimited freedom, which Jaspers called Existenz, and opens the possibility of authentic existence.
In The Question of German Guilt, Jaspers defined metaphysical guilt as the innate responsibility every German citizen bore for the acts of Nazi Germany, distinct from legal, political, and moral guilt. He argued that this collective responsibility could not be escaped by personal innocence.
Jaspers cited Spinoza as his earliest philosophical influence, with Kant becoming and remaining his central philosopher. He also drew heavily on Kierkegaard and Nietzsche, whom he considered the most important post-Kantian thinkers, and borrowed the phrase "the anti-political principle" from his contemporary Heinrich Blucher.