The result is a withering and encyclopedic indictment of a drug industry that often seems to prioritize profits over patients. Over 550 densely packed pages, Posner tells a tireless and occasionally tiring tale that reads like a pharmaceutical version of cops and robbers. There are chapters on the discovery and popularization of drugs for anxiety, for menopause, for pain management — each following a similar narrative arc. First, the author exposes how drug companies pushed medical, ethical and legal boundaries, often causing more public harm than health benefit. Then he describes lawmakers and regulators scrambling to catch up and rein in the drugmakers. And repeat.

One of the most telling episodes involves antibiotics. The mass production of penicillin during World War II helped pharmaceutical companies throw off their reputations as addictive drug pushers and rebrand themselves as producers of innovative, lifesaving products. The drugmakers also reaped massive profits from penicillin. And they were eager to earn even more, “Pharma” explains, by patenting broad-spectrum antibiotics that might be used for all kinds of health conditions. It was a retro strategy, harking back to the cure-all claims the companies had made decades earlier to promote narcotics like morphine. And it worked.

Posner recounts how many doctors came to view super antibiotics as their drugs of choice — not only for proven uses like treating bacterial infections, but “even prophylactically at the first signs of a fever, earache, scratchy throat or runny nose.” One researcher, he writes, “estimated that overenthusiasm about the new drugs meant they were prescribed unnecessarily more than 90 percent of the time.” That overeagerness drowned out troubling reports of allergic reactions to the drugs, fungal infections and the risks of antibiotic resistance. But the Food and Drug Administration, established in 1906 to oversee product safety, did not intervene, Posner notes, because its commissioner at the time did not want to be seen as an obstacle to lifesaving medications.

By 1950, pharmaceuticals had became the most profitable industry in the United States. But the mass adoption of antibiotic “wonder drugs” had opened a schism. Industry veterans, including the chief executive of Merck, insisted that medicines should be developed for people first, not for profit. Upstarts like John McKeen, the chairman of Pfizer, Posner writes, took the opposite view, arguing that it was not worth investing in drugs that would not generate substantial revenue.

In 1951, McKeen decided to use the launch of Terramycin, the company’s new broad-spectrum antibiotic, to develop a playbook for creating a blockbuster drug. For that he turned to Arthur M. Sackler, a hard-charging advertising executive who had trained as a doctor — and who decades later would become known as one of the three brothers behind Purdue Pharma, the developer of OxyContin, the painkiller at the center of the current opioid abuse epidemic.

McKeen allotted $7.5 million for the Terramycin campaign, an unheard-of sum for medical marketing at the time. Sackler used the funds for a novel saturation-marketing campaign, adapting Madison Avenue’s techniques for selling consumer goods for his own “Medicine Avenue” advertising methods. Along the way, Sackler also reset the ethical boundaries of medical marketing. “Pharma” reveals how he started one company to plant drug promotions, disguised as articles, in popular newspapers and magazines — and co-founded another company, IMS Health, to track doctors’ prescribing habits the better to influence them. It shows how the marketing maverick hired and co-opted a director of the F.D.A.’s antibiotics division to support unproven medical ideas favorable to the industry. And it exposes a misleading Sackler-produced advertising campaign that used fake doctors to promote precarious combinations of antibiotics.

Sacklers’s aggressive, and often transgressive, marketing techniques would radically remake the drug industry, contributing over the decades to the overprescription of drugs like Valium, menopause treatments, painkillers and antidepressants, ultimately resulting in untold health harms. Indeed, Purdue Pharma, the drug company owned by the Sackler brothers, adapted those influence techniques in the 1990s to deceptively market OxyContin, an opioid with a slow-release mechanism, Posner writes.