Michel de Montaigne is considered by many to be the inventor of the literary form of the essay, so the collection from which these excerpts come is important in several ways. Montaigne was a humanist and a skeptic in his philosophical approach, and essentially looked at his own experience as the first topic for examination always.
The book of Essays was one he worked on periodically throughout his life, issuing different editions, the first of which appeared in 1580. Montaigne's style of writing is sometimes stream-of-consciousness, sometimes structured in more formal styles.
Montaigne's stated task in his preface to the reader is for self-examination, but it becomes very clear that Montaigne sees himself as an 'everyman' character. He strives for full-disclosure; indeed, he writes that were he another culture 'which are said to live still in the sweet freedom of nature's first laws', then he might have appeared naked.
This is a complete set of the Essays, together with a helpful introduction and notes for reading. As Montaigne added to his essays periodically, they are not necessarily in the order he wrote them, but this collection has preserved their order according to his standards.
Montaigne's essays show a pessimism and skepticism, perhaps based on the kinds of conflicts between Catholics and Protestants going on, in France and elsewhere, as well as the periodic flare of plague. He was a humanist who saw cultures as having value internal to themselves and preferred to not universalise morals, laws and other ideas.
Montaigne was sometimes conventional in thought (seeing marriage as necessary for children, and distrusting the idea of romantic love), but other times he was very much a free thinker (particularly when it came to religious dogma or absolutist kinds of philosophical paradigms). Montaigne had respect for those who followed religious codes and ways of life, but distrusted those who tried to impose such ideas upon others.
Montaigne added to his essays twice in major ways, but did not strive for consistency or systematic ways of thinking - he declined to remove previous essays if they contradicted new writings.
Montaigne is perhaps the most important French philosopher prior to the Enlightenment. His essays remain popular because they have a sense of the modern and the current about them.