In How to Be a Stoic: Using Ancient Philosophy to Live a Modern Life, philosopher Massimo Piggliuci offers a friendly and approachable introduction to (and argument for) the Stoic lifestyle. As with many philosophical terms descending from the Greeks, Stoicism has taken on a colloquial connotation at odds with the original school of thought, with "stoic" connoting suppression of emotions, or having a "stiff upper lip". A Stoic may be mindful of her emotions and reflect on what causes them, but will still have them. Rather, it's a philosophy informed by logic and focused on the practical, with special attention paid to separating what is within one's control from what is beyond one's control.
Pigliucci traces Stoicism's origins from Socrates (the starting point for all schools of philosophy) through Antisthenes's Cynicism (similarly not to be confused with the modern shade of distrustfulness) and through to Zeno of Citium, the father of Stoicism. Each school (including competitors such as Aristotelianism or Epicurianism (not to be confused with Hedonism, itself not to be confused with wanton pleasure-seeking)) were trying to define how to live the best life and how to determine which virtues were supreme. It's hard to take exception to any of these schools on their own terms, and the differentiation seems to come down to how one prioritizes. Who could argue against the Stoic priorities of acceptance, philanthropy and mindfulness? Who would say anything against the virtues of courage, temperance, justice and practical wisdom? As Paul would say later in reference to his fruits of the spirit: "against such things there is no law".
That's a lot about labels, and labels should not be more important than the underlying attitudes they reflect. I've been aware of Massimo Pigliucci for years through his involvement with the Humanist community and appearances on Skeptic podcasts. He still happily wears the title Humanist, but takes exception to the "intolerant anger of the so-called New Atheists", some of whom he calls out by name here. Stoic seems to have taken place of pride as his preferred label, though none of the above are mutually exclusive. I myself, having read the book, would gladly add "Stoic" to many other terms that generally describe me.
Notable Stoics include the brilliant emperor Marcus Aurelius and the philosopher Epictetus. The latter makes frequent, odd appearances throughout the book as a Greek chorus (heh) for Pigliucci to ping for reactions. Usually this manifests in the form of selected quotes, though sometimes Pigliucci role-plays as the philosopher to offer commentary. Another tact is for Pigliucci to offer examples from his own life and share how Stoicism helped him avoid needless worry (such as when he deeply cut his finger and set about getting it repaired without panicking) or improve his dating prospects. One of my favorite revelations was that the famed Serenity Prayer has older, Stoic antecedents. You may be familiar with the popular prayer, passed down from Reinhold Niebuhr and popular in AA meetings: "God, grant me the serenity to accept the things I cannot change, courage to change the things I can, and wisdom to know the difference." This is pure Stoicism, minus the appeal to God. Epictetus wrote nearly two millennia earlier: "Make the best use of what is in your power, and take the rest as it happens. Some things are up to us and some things are not up to us. Our opinions are up to us, and our impulses, desires, aversions—in short, whatever is our own doing. Our bodies are not up to us, nor are our possessions, our reputations, or our public offices, or, that is, whatever is not our own doing."
It's a friendly book, if one clearly written by a philosophy professor. The terminology can get a little dense and the humor is mild, but there's a lot of good, practical wisdom to be had. If you're the highlighting type (and I am, especially reading this as an ebook), there are many passages to save for later reflection. It's also valuable for disentangling the various schools of philosophy and reifying the messages of the Greek names we see often and understand seldom. If you're looking for a little dose of the humanities, this might be just the thing for you.