As with vaccination, the advent of antibiotics hailed a new era in the treatment of communicable disease.
Interesting, then, that the concept of antibiotics may have been uncovered accidentally. In 1928, Sir Alexander Fleming left a petri dish of Staphylococci bacteria uncovered and later noted that the bacteria had been killed by a mold.
Upon further studying the mold, he discovered it was from a family called Penicillium notatum. Others soon saw the potential uses of what later came to be known as penicillin.
Today, antibiotics are used to treat a plethora of bacterial illnesses. And today, researchers are developing antivirals -- most notably, the AIDS-fighting antiviral AZT -- to deal with a host of viral illnesses as well.
Arguably, few developments have had as profound a social impact as the introduction of the birth control pill -- though its path to widespread use has been a rocky one.
Although the Federal Drug Administration approved contraception as safe in the early 1960s, it only became legal for married couples in 1965 and for unmarried couples in 1972.
But because of the Pill, countless women have been given control over their own fertility -- a concept that created a social revolution.
"Thinking about how it has transformed women's lives, in terms of family planning and the entry of women into the work force, its impact has been significant indeed," Baker said. "It was the first-ever lifestyle drug. It's not treating a disease, but it was making life better for women."
Heart disease remains at the top of the list of the country's killers. Despite this, numerous important advances in its treatment have made a considerable impact, extending and improving the lives of its sufferers.
Not the least of these advancements is surgeons' ability to operate on and repair the heart -- without putting the patient at an unreasonable amount of risk.
"Maybe the breakthrough moment was the rise of the heart-lung bypass, which made it possible to operate on the heart for more than just a few minutes at a time," Baker said. "This was followed by coronary artery bypass grafting, which is, I believe, a most important procedure."
Another development largely unnoticed by the public at large, the advent of the randomized controlled trial -- what many refer to as the gold standard of medical research -- gave medical researchers an important tool in determining which treatments work, and which do not.
Randomized trials are conducted by dividing patient populations into two groups, where one group receives the intervention to be studied while the other does not. Examining the differences between groups in these types of trials has ushered in an era of evidence-based medicine that continues to guide clinical practice on a daily basis.
"I think this is huge," Baker said. "This is really what's changed how we deal with cancer and lots of other disease, too. In the future we'll look back at this as a huge step forward."
Before the development of radiologic imaging technologies, beginning with the use of the X-ray, doctors were usually relegated to looking only for external signs of injury or damage.