Most Americans have the luxury of knowing almost nothing about tuberculosis. Because it is typically not a fact of life for us or anyone we know 99 percent of its victims are the poor residing in developing countries TB can sit comfortingly on the horizon of our awareness, perhaps colored by wisps of romanticized claptrap about John Keats and other consumptive poets whose presentiment of their looming mortality is imagined to have spiritually illuminated their genius.

TB is anything but romantic, however. It is a grindingly awful, painful, wretched affliction that preys on the weak and those already worst served by society. Roughly 5,000 more of them will die of it on the day you read this column.

This miserable state of affairs is at least an improvement over that of 1882, when TB more routinely killed one out of every seven people even in Europe and the Americas, particularly in the unhygienic, crowded cities packed by the rise of industrialism. On March 24 of that year the great microbiologist Robert Koch presented his isolation of the tuberculosis bacillus to his medical colleagues in Berlin. That date, which is commemorated annually as World TB Day, marked a turning point in humanity's struggle against the disease.

A turning point but not a decisive victory. Because TB strikes those with weakened immune systems, it has joined forces in recent decades with HIV, the other modern infectious scourge, further complicating the management and treatment of both conditions. Moreover, TB is adept at evolving resistance to antibiotics. Health authorities have helplessly watched the emergence of both a multidrug-resistant strain that survives the two most powerful treatments and an extensively drug-resistant strain that shrugs off the second-line antibiotics as well.

The depleted state of medicine's arsenal against TB is all the more galling because it could and should have been avoided. TB became aggressively antibiotic-resistant because so many patients stopped taking their pills when they started to feel better a failure of both human nature and the health care system. Economics, too, has abetted TB's survival: paltry financial incentives for serving the huge but poor market of its patients have historically dulled pharmaceutical industry interest. Fortunately, as Clifton E. Barry III and Maija S. Cheung describe in "New Tactics against Tuberculosis", philanthropic and governmental grants are reinvigorating that research.

The most promising news in Barry and Cheung's article is that scientists are beginning to understand interactions between the TB bacillus and its human hosts at the molecular level. Not only do such studies directly suggest new drug targets for future antibiotics, but they can also help the investigators develop a virtual model of TB in the body that may point to entirely novel strategies for thwarting it. Simulation might reveal the so-called emergent properties (and potential vulnerabilities) of the microorganism that are not deducible from its biochemical components.

Koch's work with TB helped to establish the germ theory as a potent tool for protecting public health. Perhaps current efforts to combat TB will prove equally useful in pioneering better ways to contain the broader health threat of antibiotic resistance, too.