A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. A pesticide may be a chemical substance, biological agent (such as a virus or bacterium), antimicrobial, disinfectant or device used against any pest. Pests include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, spread disease or are a vector for disease or cause a nuisance. Although there are benefits to the use of pesticides, there are also drawbacks, such as potential toxicity to humans and other animals. According to the Stockholm Convention on Persistent Organic Pollutants, 10 of the 12 most dangerous and persistent organic chemicals are pesticides. Silent Spring is a book written by Rachel Carson and published by Houghton Mifflin on 27 September 1962. The book is widely credited with helping launch the environmental movement. The New Yorker started serializing Silent Spring in June 1962, and it was published in book form (with illustrations by Lois and Louis Darling) by Houghton Mifflin later that year. When the book Silent Spring was published, Rachel Carson was already a well-known writer on natural history, but had not previously been a social critic. The book was widely read—especially after its selection by the Book-of-the-Month Club and the New York Times best-seller list—and inspired widespread public concerns with pesticides and pollution of the environment. Silent Spring facilitated the ban of the pesticide DDT in 1972 in the United States.