Poison has always been on the news. Most recently, there was a big story of a Bosnian war criminal, Slobodan Praljak, swallowing a poison live during a court hearing after hearing that his prison sentence would be upheld. Later, the prosecutors discovered that he had ingested potassium cyanide (KCN). As I read John Emsley’s stories in Molecules of Murder, I saw as Emsley described the very chemistry of the cyanide polyatomic ion. Right there, in the beginning of 8.2, he mentions how deadly the solutions of these salts are. Throughout the book, I gain a deeper understanding of how chemical compounds become deadly while enjoying some fascinating stories about how these poisons are utilized. The reason I chose to read Molecules of Murder was its ominous and menacing title. It grabbed my attention from the plethora of books authored by Emsley. In the introduction, Emsley talks about the first traceable poisons like the substance, white arsenic (AsO3), which I believed to be an allotrope of arsenic until I saw the chemical formula. Later, I saw how they test for white phosphorous via phosphorescence. This definitely ties back to the knowledge of the foundational chapters in AP Chemistry to understand the allotrope of white phosphorous and the chemical formulas of substances that will be continued to be mentioned throughout the book. Over the history of testing for poison, Emsley talks about the more recent methods such as chromatography and mass spectrometry. I’m instantly reminded of the lab we did: the Percent Mass of Copper Inquiry Lab. When we determined the percent mass of copper in the lab, scientists can also probably assume percent composition of what poison in the substance, and therefore determining if it is enough of a lethal dose to be effective. The first chapter, Emsley journeys through the use of ricin and how it was strangely used by the Bulgarian secret service to kill two dissidents. Ricin isn’t a chemical substance, rather it’s a biological molecule, protein. The name, ricin, sounded very familiar. I suddenly remembered that when I was watching Seth Rogen’s The Interview, they used a “ricin strip” to attempt to poison Kim Jong Un by having a “ricin strip” touch him as he shakes hands with the main character of the movie. But the book quickly discredits this idea as ricin needs to be inhaled, ingested, or injected; it is not absorbed by skin. When I heard that ricin comes from the castor bean, I was confused. I thought that we used castor oil as a laxative and drinking it would be ingesting ricin. So why don’t we die from ingesting oil from the very bean that contains ricin? Emsley explains why quite clearly: “the beans are heated to 140ºC for around 20 minutes to denature the ricin proteins.” (6). Something I learned from this book was that a poison strength is actually measured with a unit. In the book, they use the LD50, which for ricin was 0.1 µg/kg. The measurement tells us that an 80 kg human would need 8 µg of ricin to be a fatal dose. The most interesting chapters were in Part II, where Emsley strays from the biological world and delves into the chemicals ranging from chloroform (CHCl3) to polonium (Po). When I flipped to the chapter with chloroform, Emsley goes on to provide a history of what chloroform was used for and how it was utilized. The stories are very fascinating; I found it hard to put down the book when I was reading all these stories about poisons. Emsley also explains how the poisons were lodged into their bodies. When I read the story about Adelaide Bartlett poisoning her husband, I really enjoyed how Emsley explained the situation at hand: “this has taken some time before his death because some of the chloroform has passed into his intestines” (132). I can enjoy a story and learn about the chemical in process as a poison. Some of the chemicals Emsley discusses are truly scary. Take carbon monoxide (CO), no color, no smell, but absolutely deadly. I learnt how it can convert the hemoglobin in our blood cells into a “carboxyhaemoglobin” (136) that can completely take away the blood’s ability to absorb oxygen when interchanging gases at the lung’s alveoli. I had to recall a bit of some AP Biology knowledge to understand how these chemical substances affect the body physiologically.