Whether it is practiced in business, electoral politics, or international relations, most people commonsensically describe strategy as a plan or idea that guides their actions. Judging from the sheer volume of writing on the subject—especially in MBA-speak—most serious people care about having one. And yet, it isn’t altogether obvious that this is a skill that can be taught or learned the same way we might pick up coding or train for commercial truck driving.

Where to start? Any serious student of politics or war learns to assess the past, considering decisions in hindsight. The trouble comes when we try to identify threats and opportunities for what they are in the present, and work to advance our goals. By studying the “greats,” we often know what a good strategy looks like in the abstract. Yet, the world’s many distractions, unexpected challenges, and our competition’s actions—all the things that Carl von Clausewitz called friction—eat away at our ability to carry anything to fruition.

There is no exact science to forming good strategic minds. However, John Lewis Gaddis’ On Grand Strategy offers an entry point into the practice of thinking strategically. It’s a peculiar book steeped in the history of ideas, one which barely hints at a definition of strategy until the reader is 20 pages along—and this only after brief vignettes concerning Xerxes, Isiah Berlin, Jane Austin, Abraham Lincoln, and Leo Tolstoy.

Why study strategy? The answer offered by Gaddis, the Robert A. Lovett Professor of Military and Naval History at Yale University, is that we all aim to avoid failing in our responsibilities, whatever they are. Simply put, we want to plan out our actions in ways that lessen “the danger of doing dumb things.” The foresight that strategic thinking offers can benefit our whole lives.

When he finally gets around to his hinted-at definition of it, he says:

I’ll define that term, for the purposes of this book, as the alignment of potentially unlimited aspirations with necessarily limited capabilities. If you see ends beyond your means, then sooner or later you’ll have to scale back your ends to fit your means. Expanding means may attain more ends, but not all ends can be infinite and means never can be. Whatever balance you strike, there’ll be a link between what’s real and what’s imagined: between your current location and your intended destination. You won’t have a strategy until you’ve connected these dots—dissimilar though they are—within the situation in which you’re operating.

Defining one’s ends rightly, developing and using means appropriately, and relating these to one another sounds much easier in the abstract than it is in reality, and even if the connected dots look good as an ideal, they may well fail in practice. This might lead some to counsel avoiding plans entirely, but Gaddis suggests that an embrace of take-it-as-it-comes pragmatism is indeed a strategic plan, albeit one where events shape you rather than the other way around.

History and theory can work together in forming strategic minds, but as embodied in academic disciplines, neither tends to encourage their students to link the two, which opens a gap between the study of the past, and the wide range of general theories that we might use to help us navigate the present.

As Gaddis observes,

Historians, knowing that their field rewards specialized research, tend to avoid the generalizations upon which theories depend: they thereby deny complexity the simplicities that guide us through it. Theorists, keen to be seen as social “scientists,” seek “reproducibility” in results: that replaces complexity with simplicity in the pursuit of predictability.

The danger that flows from this separation is that students of either are led to neglect the relationship between “the general and the particular—between universal and local knowledge—that nurture strategic thinking.”

Gaddis argues that this lost linkage can be restored by reading many of the great books regularly taught in humanities programs across the globe, and as such, he constructs his account around ideas from a diverse array of thinkers. While such ideas can’t substitute for using judgment, they might help refine it. They can’t offer a blueprint for action, but can present patterns based “upon hard-won lessons from those who’ve gone before.”

History offers the context for making decisions, for understand the origins of our world and the reasons human beings value one thing over another. Theory helps us make comparisons, convey complexity in a manageable manner, and offer guidance about how we should proceed. At the same time, theory can help tether ends and means together, to help prevent a separation of practices and principles. He suggests that maxims that recur in great works of this tradition, like Sun Tzu’s Art of War or Niccolò Machiavelli’s Prince, help their readers to clarify what really matters.

This form of theorizing does not issue in formal laws; it offers no certainties like those some in the social sciences make their goal. Taking a page from Clausewitz, Gaddis argues that the kind of orienting theory useful for strategy should be placed “within the category of rules to which there can be exceptions, not laws that allow none.” In this sense, we should value theorizing as “an antidote to anecdotes: as a compression of the past transmitting experience, while making minimal claims about the future.” Gaddis suggests an important pedagogical order, though: While theory can train the experienced mind to understanding, this has to occur on a bedrock of contextual knowledge of the kind that practitioners can acquire through work, and that students acquire by reading widely in history. Pruning theory with such already-acquired historical knowledge is key to using it well.

Gaddis contrasts pairs of ideas and thinkers throughout the book to accomplish his goal of strategic education. The clash between ideas held by Augustine and Machiavelli offers the most striking and lasting contrast, one that he argues recurs frequently throughout our history. For him, these thinkers reflect the struggle between souls and states.

With Augustine, Gaddis argues, seeking God and the goods of this world in light of our understanding of the truth offers the best path toward living well. To formulate a strategy without that in mind would be to deny the truth about man. Order stands in tension with justice; the means we use can undermine the ends we seek. Strategy becomes a moral art, one focused not just on aligning ends and means in a temporal sense, but also the needs of the soul.

For a Machiavellian sensibility, eternal truth offers no guidance for how to live in the here and now. Events are half man-made, half the product of fortune, and as Gaddis notes, “zero percent God.” We must recognize that man is “however precariously, on his own.” In this view, the “skills needed are those of imitation, adaptation, and approximation.”

Using this contrast between Augustinian and Machiavellian strategy, Gaddis presents informative sketches of Elizabeth I of England, Philip II of Spain, The Federalist Papers, Edmund Burke, Napoleon, Lincoln, and many others.

Gaddis offers a perceptive reading of the strategies informing the American Revolution, and clearly understands the ways that The Federalist can be read strategically. By framing Lincoln’s conduct of the Civil War within his notion that statecraft requires reconciling the competing demands of souls and states, he walks his readers through the complexity of judgment in high command. And he offers pointed reminders of ways that a successful strategy sometimes requires morally painful compromises. Using Isiah Berlin’s experiences as a diplomat in World War II, Gaddis observes that the “price of victory . . . would be the denial of justice, because the price of justice could be the denial of victory.” Small nations would suffer as a result, but the war would be won.

The book offers many bold and even jarring opinions. Gaddis enthusiastically endorses Machiavelli over Augustine, labeling the latter as a “ponderous Pangloss.” But he does this on the basis of a very peculiar reading of Augustine. He views the City of God as “a fragile structure within the sinful City of Man,” and avers that Augustine “was never wholeheartedly a monotheist” because of his worship of reason. Machiavelli’s worship of what works leads Gaddis to argue that the Florentine “outs his own monotheism by seeking, above all, to minimize mess.”

But these eccentric opinions remain outliers in the context of a book that offers such a strong starting point for thinking about how to tether abstract ideas to our concrete realities. Especially if Gaddis is read alongside his colleague Charles Hill (Grand Strategies: Literature, Statecraft, and World Order, 2010), an attentive student will encounter a compelling case for the idea that great books can teach strategic understanding. Gaddis reminds us that best minds of the past can illuminate the perennial challenges of politics, and that as we walk the tightrope between means and ends, such wisdom can mean the difference between life and death.