Published in 1963, Markings was the only book written by Dag Hammarskjöld, the first UN secretary general. The journal was discovered after his death, with a covering letter to his executor describing it as "a sort of White Book concerning my negotiations with myself -- and with God." Hammarskjöld died in a mysterious plane crash while on a peace mission in Africa. The CIA attributed the crash to the KGB. There’s an interesting description of Hammarskjöld life on Wikipedia here.

Markings intermingled prose and haiku poetry in a manner similar to the 17th-century Japanese poet Basho in his Narrow Roads to the Deep North. It was an unstructured journal in which he recorded the main points in the movement of his life, including some that were painful and involved the failure of important projects.

I don't know Who ‑- or what -‑ put the question, I don't even know when it was put. I don't even remember answering. But at some moment I did answer Yes to Someone ‑ or something ‑ and from that hour I was certain that existence is meaningful and that, therefore, my life, in self‑surrender, had a goal.

We are not permitted to choose the frame of our destiny. But what we put into it is ours. He who wills adventure will experience it—according to the measure of his courage. He who wills sacrifice will be sacrificed — according to the measure of his purity of heart. . . In our age, the road to holiness necessarily passes through the world of action.

The longest journey is the journey inward.
- Markings, Dag Hammarskjöld