"Dopesick," Beth Macy, Little, Brown & Co., 376 pages, $28.

Early warnings haunt the pages of “Dopesick: Dealers, Doctors, and the Drug Company That Addicted America,” a harrowing, deeply compassionate dispatch from the heart of a national emergency. The third book by Beth Macy — the author of “Factory Man” and “Truevine” — is a masterwork of narrative journalism, interlacing stories of communities in crisis with dark histories of corporate greed and regulatory indifference.

Macy began investigating the drug epidemic in 2012 as it seeped into the suburbs around her adopted hometown, Roanoke, Va., where she worked for 20 years at the Roanoke Times. The further Macy wades into the wreckage of addiction, the more damning her indictment becomes.

Particularly grotesque is the enthusiasm with which Purdue Pharma peddled its pills. In the first five years, OxyContin was on the market, total bonuses for the company’s sales staff grew from $1 million to $40 million. Zealous reps could earn quarterly bonuses as high as $100,000.

Doctors were plied with all-expense-paid resort trips, free tanks of gas and deliveries of Thanksgiving turkeys. There were even “starter coupons” offering new patients a free 30-day supply. Sales rocketed into the billions.

The final third of “Dopesick” is dedicated to recovery. While Macy offers some glimmers of hope, what echoes long after one closes this book are the unsettling words of Tess Henry’s mother about her daughter: “There is no love you can throw on them, no hug big enough that will change the power of that drug.”