In the early 1900's it was easy to get away with murder in New York City, especially if you used poison. Poison was almost impossible to detect in a corpse, and most of New York City's coroners had no medical training at all. Coroners were political positions, and political parties often fixed elections to give jobs to their supporters. That meant that the guy who turned up to determine cause of death could be a plumber or the milkman.
Corruption was rampant, so even if cause of death was pretty obvious, you could always bribe the coroner to put down natural causes on the death certificate. Someone once tried to bribe a someone to put down suicide on the death certificate of a guy who'd been shot four times in the leg, arm, shoulder, and heart. Didn't want the stigma of a suicide attached to your family? Just bribe the coroner, and he'd conveniently write aneurism on the death certificate, despite the fact that the man was found dead with a gun in his hand and a bullet wound in his mouth.
The city coroner was notorious for showing up drunk for work. By 1918, the public outcry was so great that the city was forced to hire a real, qualified medical examiner. There were three men who passed the exam, but the mayor was mad that he couldn't reinstate his buddy, the old city coroner, into the position. He was so mad that he tried to get all three men arrested on trumped up charges so they'd be disqualified for the job. Luckily for the three men that didn't work. The mayor refused to hire the man with the highest exam marks. He knew he couldn't get away with hiring the man who came in last, so he picked the man who came in second: Charles Norris. Unfortunately, from the mayor's point of view, Charles Norris turned out to be the very best man for the job.
Charles Norris loved forensic medicine, and he was passionate about his job. He was determined to see that the victims' families saw justice. The first thing he did was hire a brilliant chemist named Alexander Gettler. When the city wouldn't give them any money to set up a forensics lab, Norris paid for it out of his own pocket. He was willing to do anything it took to see that murderers didn't walk free, whether that meant badgering the mayor for more money for supplies, or paying a man's salary himself during the Depression.
Like Norris, Gettler was a workaholic, and just as devoted to his field. If a test for a poison didn't exist, he'd invent it. If there was a test, he'd refine it until he could detect minute amounts of poison. Together, Norris and Gettler revolutionized forensic medicine, and made sure that poisoners couldn't get away with murder.
I stayed up two nights in a row to finish this book, although I did manage to creep myself out the first night by reading about murderers at two in the morning. Deborah Blum even made what should have been very dull parts on how poisons work at a molecular level completely fascinating. I am definitely going to look for her other books. I suspect she could make a scholarly treatise on the history of tablecloths gripping.