SUMMARY OF THREE MEN IN A BOAT - 
Three friends named Jerome, George, and Harris smoke together in their apartment in London. They are all hypochondriacs and discuss their illnesses. After researching diseases at the British Museum, J. has recently come to the conclusion that he has every disease known to man except for housemaid’s knee. The men decide that a vacation will be good for their health, and after some deliberating, they decide to spend a week rowing up the Thames with their dog, Montemorency.
The men make arrangements for the trip. They decide to bring a cover for the boat and sleep in it, rather than a tent or an inn. They compile a long list of items to bring but quickly realize that they should only bring the essentials. Although they are friends, Jerome seems to dislike Harris, and compares him at length to Jerome’s incompetent Uncle Podger. They end up bringing a hamper of food, clothing, a cover for the boat, and a methylated spirit stove for cooking. Packing takes a long time because the men keep forgetting items they need.
On the first morning of the trip, the men oversleep but eventually get on a train to Kingston, from which they will embark on their journey. J. describes some local landmarks, including Hampton Court and some pubs that Queen Elizabeth dined in. Harris tells a story about getting lost in the hedge maze at Hampton Court. The men pass through their first lock––that is, a canal set off from the river that allows boats to pass through a steep area. J. comments on how irritating it is when women wear ‘boating clothes’ that are too delicate to get wet. George separates from the group to do some work for his employer in Shepperton. Harris proposes visiting a cemetery to see an interesting tombstone, but J. rejects this idea. Harris falls into the food hamper while trying to get some whiskey.
When J. and Harris stop to lunch on the riverbank, a man accuses them of trespassing and tries to blackmail them. Harris, a large man, physically intimidates the visitor and they journey on. J. warns readers not to be taken in by these thugs, who usually do not work for the landowner. He then recounts an embarrassing story when he and Harris both made fools of themselves at a pretentious party––Harris by singing a comic song, and J. by pretending to speak German. Jerome describes a few more local points of interest, and the two men reunite with George in Shepperton.
Harris and Jerome convince George to tow the boat from the shore––an arduous task that can lead to problems if the tower becomes distracted. Jerome  recalls various incidents when he was boating and the tow-line became tangled or detached entirely. The men have a satisfying dinner and sleep in the boat. The next morning, they wake up early and George tells Jerome a story about forgetting to wind his watch and starting his work day six hours too soon. Jerome falls in the water and Harris attempts to make scrambled eggs but fails. As they pass Magna Charta Island, J. describes what it would have been like to be a peasant when the Magna Carta was signed.
The men pass Datchet and recall trying to find a place to sleep there on another trip when the inns were full. That night, they sleep at an inn in Marlow. Montmorency chases a large cat but is too intimidated to attack it. The next day, they pass more historical landmarks including Bisham Abbey. They run out of drinking water and are disgusted when a local lock-keeper suggests that they drink out of the river. Harris falls off the edge of a gulch while trying to eat supper. The next evening, they cook Irish stew and George plays the banjo. However, he is a beginner and his music is so awful that Harris and J. persuade him not to play for the rest of the trip. George and J. go for drinks in the town of Henley that night, but get lost on their way back. When they eventually find Harris sleeping in the boat, he explains that he had to move it because he was attacked by a flock of aggressive swans.
J. describes some of the mishaps that he and George had when they were learning to row. They pass through Reading without incident, although J. does offer a brief history of the town. As they approach Goring, they discover a woman’s corpse floating in the water. They later learn that she drowned herself after having a child out of wedlock and finding herself unable to support it. The men attempt to wash their clothes in the Thames, but the clothes only come out dirtier than before. That night, they drink at a pub in Wallingford with a large fish hanging on the wall. All of the patrons claim to have caught the fish themselves, but George accidentally knocks it over and the men realize that it was made of plaster of Paris.
The friends continue toward Oxford, where they will turn around and row back toward London. J. describes a time that he and George went rowing and, by falling over at exactly the wrong moment, managed to ruin a professional photographer’s pictures. J. describes the attractions of Dorchester, Clifton, and Abingdon, which include Roman ruins and the grave of a man who fathered 197 children. They manage to navigate a difficult stretch of river near Oxford and spend two days there. J. interrupts the story to warn readers about renting a boat in Oxford because they tend to be of poor quality.
On the way back from Oxford, it rains and the men find themselves cold, wet, and miserable. They soon decide to abandon the boat and spend the rest of the trip at an inn(hotel). That night, they enjoy a delicious supper and toast their decision to abandon the boat when they did. The book ends with the three men (and the dog) enjoying a fine meal in a London nightclub, toasting themselves and their friendship. Montmorency barks in agreement.