Pipe bombs stashed at the finish line of a beachside “fun run.” Pressure cookers in Manhattan’s busy Chelsea neighborhood, packed with steel nuts and ball bearings purchased on eBay. Citric acid, fuses, circuit boards. A magazine with articles like “Make a Bomb in the Kitchen of Your Mom.”

The trial that begins Monday in Federal District Court in Manhattan will lay out the trove of evidence behind the creation and deployment of bombs in New York and New Jersey just over a year ago that collectively tore through metal, glass and the city’s sense of security. And prosecutors, using evidence from the defendant’s internet searches, phone videos and text messages, will seek to place the man, Ahmad Khan Rahimi, who lived in Elizabeth, N.J., above his father’s chicken restaurant, squarely on the misfit-to-jihadist path familiar in terror attacks worldwide.

No one was killed in the bombings, and Mr. Rahimi, a 29-year-old Afghan-born United States citizen, has pleaded not guilty. Prosecutors said 31 people were injured, with some expected to testify at the trial and to tell of glass and metal fragments piercing their limbs and faces.

But for all the havoc wrought during the region’s two days in a grip of fear and an interstate dragnet, the evidence collected is a reminder of how much worse it could have been. Of the four devices set to explode, only one did as planned, a combination of bad luck and apparent mistakes that almost certainly saved lives.