Understanding science is hard. Writing about science—writing well, at least—is harder. Approach the front lines of any scientific field and the air becomes thick with acronyms and baffling, yet necessary, jargon. But we need good science journalism more than ever. Measles, a disease once almost eradicated in the U.S., is roaring back in several parts of the country. The cause isn’t poverty or lack of access to vaccines; it is a seductive sort of anti-scientific thinking that values “lived experience” over legitimate research. In Los Angeles’s wealthiest neighborhoods, some schools have vaccination rates as low as those in war-ravaged South Sudan. 

We can’t all be scientists, so we rely on mainstream science journalists to distill important research into a form we can follow and remember. The best books in the field don’t just help us understand complex ideas, they take us inside the process of scientific discovery. They show us how science works, which is just as important as knowing what facts it uncovers.

Matt Richtel, a reporter for the New York Times, does this and more in his new book, An Elegant Defense. If your image of the immune system dates back to high-school biology—white blood cells marching into battle against nasty pathogens—you have some catching up to do. We all do. Richtel focuses mostly on research conducted since the early 1980s, when HIV/AIDS—“the 9/11 of immunology,” one researcher calls it—revealed just how little we really knew about our bodies’ defenses. The effort to understand HIV wound up dovetailing with concurrent work on autoimmune disorders and cancer. The result has been a revolution in our knowledge of the immune system. The treatments emerging from these breakthroughs, another researcher says, will be “as significant as the discovery of antibiotics.” 

Getting readers up to speed on all these new discoveries would challenge any writer. Richtel introduces us to a bewildering host of internal disease fighters: monocytes, macrophages, B cells, T cells, natural killer cells, Interferon A, Interferon B, Interleukin 1, Interleukin 2, and so on. He does his best to tame the jargon, though at times he’s reduced to apologizing for it. (“Dear reader, please soldier on!” he begs—unnecessarily—during a particularly dense patch.) But Richtel has two powerful devices to guide us through these thickets of information.

The first is a wonderful analogy that recurs throughout the book: He compares the human body to a raucous outdoor festival, “a take-all-comers bash…coursing with every life-form that happens by.” The various agents of our immune system circulate through this wild party keeping an eye out for troublemakers. Some immune cells behave like trigger-happy cops, others like spies, still others like janitors, carting away cellular detritus. These cells constantly talk to one another, not just when rallying troops to attack a particular pathogen, but also when it is time to stand down. Quite often, they’ll agree to let certain questionable partygoers celebrate unmolested.

This last function, the ability to shut off our immune response, turns out to be key to our survival. “The immune system is a loaded gun,” one researcher explains. Sometimes it has a hair trigger for what should be harmless foreign bodies—pollen, cat dander, nuts—and we experience the free-ranging inflammation we know as allergies. When the system fires indiscriminately at our own tissues, we suffer devastating autoimmune syndromes such as lupus, Crohn’s disease, and rheumatoid arthritis. “Like an out-of-control police state,” Richter writes, “an unchecked immune system can grow so zealous that it turns as dangerous as any foreign disease.”

Our immune system’s struggle to distinguish “what is self and what is alien” is fantastically complex. After all, we need to eat and absorb those alien nutrients into our bloodstream. And our guts are jammed with a “microbiome” of helpful bacteria that must be allowed to thrive. On the other hand, sometimes our own cells go rogue, multiplying out of control and becoming cancerous. The immune system needs to detect that too, marshaling the gendarmes to attack these formerly friendly cells.

It’s a tightrope act: When the immune system is too sluggish, as is the case with AIDS sufferers, the body is overwhelmed with opportunistic infections. But we also face a growing threat from overactive immune systems. Twenty percent of the population today suffers from some form of autoimmune disease. Our obsessively sanitary lifestyles are partly to blame: When our immune systems don’t have enough exposure to actual pathogens, it seems, they turn hypersensitive. One researcher advises that children should “eat a pound of dirt a day.” He’s only half kidding.

Richtel’s other helpful device is people. He writes that he wants his book to be “less textbook than tale,” and he succeeds partly by explaining the science through the stories of the people most closely involved. We meet many of the researchers behind key breakthroughs, including the National Institutes of Health’s Anthony Fauci, who helped crack the code of HIV/AIDS. Richtel also follows the stories of four people whose lives were dramatically shaped by the quirks of their own immune systems, two men and two women living with either HIV, an autoimmune disorder, or cancer. 

The most compelling of these concerns Richtel’s lifelong friend Jason Greenstein, a quirky free spirit who was struck with an aggressive case of Hodgkin’s lymphoma in midlife. In a dual role as friend and journalist, Richtel accompanies Greenstein in his long journey through treatment. Cancer is one of those diseases that can trick the immune system into standing down. Greenstein’s doctors go to extraordinary lengths to try to reboot his, including a bone-marrow transplant. Richtel calls this “a terrible, evil, nuclear-winter-level therapy” but explains how, if successful, the transplant provides new stem cells that can rebuild a patient’s immune system from scratch. 

Seeing Greenstein’s doctors push the outer limits of treatment—and following the long efforts to unlock the secrets of HIV/AIDS and autoimmune illnesses—gives us an appreciation for the grueling work behind every breakthrough. Scientific knowledge isn’t pronounced from on high by lab-coated authorities. It is earned through daily struggle and tested through endless setbacks. Books like An Elegant Defense give mainstream readers insights into that process, insights that run deeper than those a textbook might provide. When we understand how science really works, perhaps we will be a bit less susceptible to anti-scientific seductions. Richtel’s elegant analogies and compelling human stories will help us remember the basic concepts of modern immunology long after the jargon and acronyms have been forgotten.