I wouldn't be surprised if this isn't considered one of Montaigne's most important essays. I won't try to break it down, like I have the others. Instead I want to share some of the parts that most made an impression on me.
"I never seriously settled myself to the reading of any book of solid learning but Plutarch and Senaca; and there, like the Danaides, I eternally fill, and it as constantly runs out; something of which drops upon this paper, but little or nothing stays with me." When I was in my teens and twentys I read and reread my favorite authors (especially Robert Heinlein) and it is quite fair to say that they shaped me. I can see where the history of Plutarch especially would be a good guide to read again and again. The history of important people is always instructive.
"For these are my own particular opinions and fancies, and I deliver them as only what I myself believe, and not for what is to be believed by others. I have no other end in this writing, but only to discover myself..." The writings of Montaigne are very intimate and this is the reason why. He was on an enormous voyage of self discovery and he shared the trip with whoever would read him.
"...it is no hard matter to get children; but after they are born, then begins the trouble, solicitude, and care rightly to train, principle, and bring them up." Couldn't help but chuckle at this. Yes, children are much easier before they're born. And yes, the work of bringing them up takes great effort.
"A mere bookish learning is a poor, paltry learning; it may serve for ornament, but there is yet no foundation for any superstructure to be built upon it..." A huge theme for Montaigne. Learning is good but is only part of an education. The moral part is more important.
"It is not enough to fortify his soul; you are also to make his sinews strong; for the soul will be oppressed if not assisted by the members..." Another theme of Montaigne, that a strong body is also important to a full life. When I was young I somehow convinced myself that because I was 'bookish' I should stay away from working with my hands. This was one of the bigger mistakes in my life.
"...even in conversing with men I spoke of but now, I have observed this vice, that instead of gathering observations from others, we make it our whole business to lay ourselves open to them, are are more concerned how to expose and set out our own commodities, than how to increase our stock by acquiring new." This is a vice that I suffer from too. Instead of listening, really listening, I too often spend my time shaping my rebuttal. Lord knows how much I've missed out on.
"In this conversing with men, I mean also, and principally, those who only live in the records of history; he shall, by reading those books, converse with the great and heroic souls of the best ages." This is a lesson that I'm sure Montaigne gained from his readings of Plutarch and Seneca. He worked very hard at really learning all that he could from the ancients.
"The fear was not that I should do ill, but that I should do nothing; nobody prognosticated that I should be wicked, but only useless; they foresaw idleness, but no malice;" What a sad fate, to grow up to be useless.
It's a long essay but if you haven't read it yet, it is well worth the time.