Determined to write a non-fiction book entitled The Day the World Ended about the day the nuclear bomb was dropped on Hiroshima, freelance journalist John travels to Ilium, New York. He meets the family of the deceased Dr. Felix Hoenikker, one of the fathers of the nuclear bomb. John learns that Frank Hoenikker, the doctor's fugitive son, lives on the Caribbean island of San Lorenzo. Among an odd assortment of characters in the tiny island dictatorship, John encounters a former Calypso singer turned religious prophet named Bokonon and becomes a convert. John learns that each of the three Hoenikker offspring owns a vial of Ice-nine, the doctor's final invention. Ice-nine is so deadly that a single drop will freeze all the water on Earth, making the planet uninhabitable and killing all living things. John is just about to assume the presidency of San Lorenzo when an accident releases the Ice-nine into the ocean. Instantly, all plant and animal life is killed. Only a few ants and six humans survive the cataclysm.

Arriving on the island of San Lorenzo, John is surprised to find that the people are malnourished, impoverished, homeless and diseased. The Americans who accompany him on his journey are greedy, destructive or misguided. The dictator of San Lorenzo, Papa Monzano, is the worst of all. Each of the Hoenikkers has used his or her vial of the fatal Ice-nine for their own purposes. Angela, Frank and Newton are each willing to sacrifice the entire world for love or money.

Papa Monzano commits suicide by ingesting the Ice-nine. John, with the Hoenikkers' help, isolates the dangerous crystal when an explosion sends Papa's body plunging into the sea. Instantly, all the water on the earth freezes and almost all life perishes. John manages to survive along with Newt and Frank Hoenikker and the greedy Crosbys.

The author, Kurt Vonnegut, is a master of satire. Vonnegut debunks everything that humans rely on to give meaning to life, including religion, science, the truth, business, power, politics, social groups, families, governments, nations, art and romance. He skewers the concepts of fate and self-determination, good and evil. Even nihilism - the belief that life is essentially meaningless - is subjected to scorn. Yet, the author never offers an alternative to these false gods. Instead, the novel is a farce perpetrated by men who are constantly seeking an elusive meaning in life.

Vonnegut credits his background as a reporter for his powerful yet unadorned style. Cat's Cradle, Vonnegut's first best-seller, was accepted by the University of Chicago as the author's belated thesis in anthropology. Vonnegut had attended the university from 1945 to 1947. His first thesis, on the similarities between Cubist paintings and the Native American uprisings of the late 19th century, was rejected by the University as unprofessional. Vonnegut was finally awarded his degree, an M.A. in anthropology, in 1971, at the age of 49.

Vonnegut's novel has a unique structure. It is comprised of 127 chapters averaging just one and a half to two pages each. Because of this unique structure, within this study guide, chapters have been grouped according to topic for easier reading.