"My beloved soul!" - this is how Martin Heidegger addressed his fiancée and later wife Elfriede for more than fifty years. "...the letters we exchange have something absolute that we cannot yet realize the conditions of an unhindered life with living closeness at all times. The letters are a way for us to be spiritually together, of course somewhat pale, but on the other hand unhindered and complete," he wrote to her shortly before their marriage. In their almost sixty years of marriage, the couple often lived apart, so correspondence was almost until the end an important form of communication.

His letters are snapshots that demonstrate the beginning, the peaks, the turning points, the crises, and the everyday life of the philosopher - the construction of the famous hut in Todtnauberg, the difficulties for his relocation to the chair of philosophy in Marburg, the financial problems, his view of women, his working method.

Elfriede kept countless cards and letters in a box, except for three that are in Martin Heidegger's remains at the German Literary Archive in Marburg. In 1977, after a final check, Elfriede handed the key to this box to her granddaughter Gertrud Heidegger, with the condition that it be opened after her death.

The selection from Martin Heidegger's numerous letters to his friend, fiancée, and wife allows us to take a glimpse into their married life, friendships, thoughts, and beliefs.