The Essays by Michel de Montaigne (1580)

TL;DR It is a series of Essays with a self-examination or a self-exploratory aim, discussing various topics that piqued Montaigne's curiosity. Had Montaigne lived today he would be writing long form blogs. It is influenced by the stoics; some of more well known philosophers such as Socrates, St. Augustine and others. In the philosophical branch, he is lumped under Skepticism. From the writings, he seems like a regular guy, regular in the sense that he's like a neighbor, like an old uncle, a really smart, and at times self-deprecating uncle.