Salo Wittmayer Baron was the first person to hold a chair in Jewish history at an American university and the author of numerous groundbreaking studies in the field. In an essay first published in 1989, he tells the story of his passion for collecting books, and how he assembled his enormous private library, most of which now resides at Stanford University:

As a child of four (in 1899) in Galicia I was introduced to the study of the Bible and its various interpreters. Less than two years later my father paraded me before relatives and friends as a student of the Talmud together with its commentaries. At the same time I excelled in mathematics and the game of chess. . . .

Soon thereafter the Russo-Japanese war (1904-1905) introduced me to the world of journalism. I began to devour every page on that subject in the Polish, German, and Hebrew newspapers and magazines that arrived at our home. For some reason, when I was about nine years old, I became an admirer of the British empire. For hours I would pore over a map, figuring out how many days it would take to travel by ship from London to Sydney, for example. . . .

But not until I was a teenager did I become a passionate buyer of books. Both of my parents had been book-lovers. My mother had a good general knowledge of Polish and German literature, which she cultivated throughout her life. She also spoke French fluently. With her aid I learned to buy books by mail, especially from major German booksellers. Since I received a small weekly allowance from my parents, I established at the age of fourteen or fifteen a regular exchange with one particular book dealer in Berlin, who sent me his catalogues; from them I would choose one or more items. Later he would choose one or two recently arrived titles that he knew would be of interest to me. He sent them directly to me with the understanding that I could return them, in case I found them less than desirable. In this way I assembled quite a collection of German and later also Hebrew books. This marked the beginning of my book-collecting mania.

When the IDF finally caught up with the late Hamas leader Yahya Sinwar, he wasn’t deep inside a subterranean lair, as many had expected, but moving around the streets the Rafah. Israeli forces had driven him out of whatever tunnel he had been hiding in and he could only get to another tunnel via the surface. Likewise, Israel hasn’t returned to fight in northern Gaza because its previous operations failed, but because of its success in forcing Hamas out of the tunnels and onto the surface, where the IDF can attack it more easily. Thus maps of the progress of the fighting show only half the story, not accounting for the simultaneous battle belowground.

At the beginning of the war, various options were floated in the press and by military and political leaders about how to deal with the problem posed by the tunnels: destroying them from the air, cutting off electricity and supplies so that they became uninhabitable, flooding them, and even creating offensive tunnels from which to burrow into them. These tactics proved impracticable or insufficient, but the IDF eventually developed methods that worked.

John Spencer, America’s leading expert on urban warfare, explains how. First, he notes the unprecedented size and complexity of the underground network, which served both a strategic and tactical purpose:

The Hamas underground network, often called the “Gaza metro,” includes between 350 and 450 miles of tunnels and bunkers at depths ranging from just beneath apartment complexes, mosques, schools, hospitals, and other civilian structures to over 200 feet underground. . . . The tunnels gave Hamas the ability to control the initiative of most battles in Gaza.

One elite unit, commanded by Brigadier-General Dan Goldfus, led the way in devising countermeasures:

General Goldfus developed a plan to enter Hamas’s tunnels without Hamas knowing his soldiers were there. . . . General Goldfus’s division headquarters refined the ability to control forces moving underground with the tempo of the surface forces. Incrementally, the division refined its tactics to the point its soldiers were conducting raids with separate brigades attacking on the surface while more than one subterranean force maneuvered on the same enemy underground. . . . They had turned tunnels from obstacles controlled by the defending enemy into maneuver corridors for the attacker.

This operational approach, Spencer explains, is “unlike that of any other military in modern history.” Later, Goldfus’s division was moved north to take on the hundreds of miles of tunnels built by Hizballah. The U.S. will have much to learn from these exploits, as China, Iran, and North Korea have all developed underground defenses of their own.