At first I thought the title was stupid, but I see the author's point. Guess what the #1 all-time single greatest killer of human beings is? Well, the fact that I'm asking in a book review about tuberculosis gives it away, but... yeah! Believe it or not, it IS tuberculosis. I secretly guessed it might be war, but the author addresses this. Taking the beginning point of humankind as 35,000 years ago (kind of arbitrary, but based on some carbon-dated artifacts) most of human history is in small agrarian or hunter-gatherer societies whose warfare was extremely limited. With the Romans, etc we start to see war on a larger scale (the Roman routing at Teutoberg Forest saw an estimated 10,000- 20,000 casualties), and it isn't until Napolean and then the 20th century that warfare even begins to rival infectious diseases as a major cause of human deaths.
How about cancer? Not even close. Most cancers appear in mid to late adulthood, as the result of longstanding insults (smoking being the most obvious example). It is only recent in human history that most people have lived long enough to be at risk for the cancers we most fear today: lung, breast, colon, and (mostly in Asia) liver and stomach.
No, infectious diseases are by far the greatest killers. Malaria is a contender for the top title, but unlike tuberculosis, malaria only occurs in certain climates and geographical regions. Tuberculosis is seen in every climate, and every geographical area. Skeletal evidence shows it was a widespread killer in the Americas pre-Columbian "discovery".
... So you might think that the discovery of a "cure" (I use the word advisedly, since resistant strains of TB have arisen, which we cannot cure, but the discovery of streptomycin was at the least a major breakthrough) to TB would be the most celebrated event of the last century. For some reason it wasn't... probably because:
a) The discovery of streptomycin, and later isoniazid, both occurred during World War II, and were overshadowed by the much more immediate and harrowing news of war developments.
b) As happens so often, multiple groups around the world were working on very similar projects concurrently, and there is some dispute over who deserves how much credit, and who was first, who was the "real" genius who deserves all the accolades, and who is a mere poseur, whose work is derivative (if not outright theft, if you believe certain parties). Sadly, the discovery of the first effective anti-tuberculins were soured to a larger-than-usual degree by this sort of infighting. Groups at the Mayo Clinic, Merck Pharmaceuticals, a famous Swedish TB sanitarium (whose name escapes me at the moment) and Bayer Pharmaceuticals all lay claim on producing the first anti-tuberculosis drugs. The bitterness is magnified in this case because these scientists' respective countries (the USA and Germany) were at war at the time of discovery, and because the Bayer patent -having been filed by the Third Reich- was nullified upon surrender, and Bayer lost millions, if not billions, in revenue on the drug, while that was all getting cleared up.
As for the science of it all.... it's a good read. It starts with a soil scientist, Selwin Wacksman, teaching at Rutger's agricultural college in the 1920s. He has no medical training or ambitions, but is rather a super-specialized microbiologist dedicated to discovering and cataloging the germs which inhabit soil. He notices that beneath the ground, soil microbes wage a continuous war on one another, producing toxins which beat back their competitors (for nutrients). One odd organism in particular- Acetomyces- seems to be a sort of hybrid between fungus and bacteria, and it has evolved the ability to make a toxin which kills streptococcus.. a soil bacteria which also happens to be a cause of deadly pneumonia. Wacksman doesn't develop that idea to its fullest- credit for the clinical implementation of penicillin goes to Alexander Fleming.. but Wacksman learns from this, and later notices a similar effect by another organism which seems to inhibit the growth of tuberculosis.
The cast of characters blossoms after this, and frankly, it's difficult to keep them all sorted out... in fact, I stopped trying eventually, which is one reason this is just a 3-star read... but anti-TB research really took off after that.
An odd tidbit of information one scientist noticed: household aspirin (salicylic acid) has an odd effect on the tuberculosis organism: it causes the organism to consume much more oxygen than it otherwise would. By slightly modifying aspirin by adding an amino group to it, PAS (para-amino salicylate) is created- which has the extraordinary effect of not killing the TB bug, but rendering its metabolism dormant, giving an infected patient's immune system sufficient opportunity to mount an effective attack. PAS was the first "wonder drug" against TB, and the moniker is no exaggeration. This book is filled with anecdotes of stunning medical turnarounds by institutionalized TB patients who were all but left for dead, and within weeks of starting PAS therapy were able to completely recover, eventually being discharged back to their communities, with no detectable infection.
After PAS came Isoniazid- an even more potent anti-tuberculin, and even today a mainstay of anti-TB therapy. Like PAS, it has a surprisingly simple chemical structure, and its mechanism shuts down the bacteria's metabolism, allowing host defenses to do the dirty work of actually fighting and destroying the bug. Unfortunately, isoniazid is a far from perfect drug. It is incredibly powerful against TB, but it also has a long and nasty list of side effects... liver damage, neurologic effects (including seizures), severe stomach cramping and diarrhea, terrible skin rashes, etc.
The last drug discussed is Rifampicin, which came into more widespread use in the 1960s, and rounds out the arsenal of modern anti-tuberculins. In combination, it was learned, TB could be beaten down from the #1 killer of humans, to a problem health officials in the developed world came to regard as nearly eradicated by the early 1980's.
And that's the final portion of the book... the advent of AIDS, and the resurgence of TB. Since AIDS destroys the immune system, these TB drugs which merely slow down TB without killing it are less useful. AIDS patients succumb to tuberculosis even on the strongest course of therapies, because they have an impaired ability to metaphorically throw punches at the bug, even when PAS, Isoniazid, and Rifampicin are (again, metaphorically) holding it down. Worse still, as TB resurges, and the old mainstay therapies are used more and more widely, it has created conditions where resistant strains are bred. The book was published in 1992, and warns of a day when a "triple resistant" tuberculosis will make its way through the population. Well, it's 2014, and that day has come. Powerful drugs to fight HIV itself are now available, but multiresistant TB is well-established in the world, especially (but not exclusively) in India, Latin America, and Sub-Saharan Africa. Ebola is more dramatic, and gets more press, but there is every danger that TB may emerge in the next century to once again become the #1 killer of (wo)men.