Four years into his university education, the Kant family suffered another set-back. In 1744, Kant’s father, Johann, suffered a stroke. Immanuel, twenty years old and now the head of the family, attended to his father’s health and stopped attending classes the following year. He started writing on natural philosophy around this time, trying to determine the properties of force, a theme much in currency at the time. In 1746, he buried his father, wrote the bulk of his first work, submitted it to the censor, and secured a publisher. A year later, in 1747, he completed the Thoughts on the True Estimation of Living Forces, settled the family’s affairs, found homes for his younger brother and three sisters, and moved in with another student. The Living Forces is his first known text, first publication, and first book.