"Mr. Know-All" is a short story by W. Somerset Maugham that was first published in Harper's Magazine in 1951. The story is about a man named Max Kelada, who is a passenger on a ship traveling from San Francisco to Yokohama. Kelada is a self-proclaimed expert on everything, and he quickly becomes the center of attention on the ship, impressing the other passengers with his supposed knowledge and wisdom.
As the story unfolds, we learn that Kelada is not the wise and knowledgeable man that he appears to be. In fact, he is a fraud and a liar, who has no real expertise in any subject. Despite this, the other passengers are completely taken in by him, and they continue to listen to him and seek his advice.
One of the other passengers on the ship is a man named Sam Marlowe, who is an honest and straightforward person. Marlowe is not impressed by Kelada and sees through his facade, but he keeps this to himself and does not confront Kelada directly.
As the ship approaches its destination, a storm hits and the passengers become worried about their safety. Kelada, who claims to be an experienced sailor, tries to calm their fears and assures them that everything will be alright. However, his assurances turn out to be empty, and the ship is eventually damaged by the storm.
In the end, Kelada's true colors are revealed, and the other passengers finally see him for what he really is: a dishonest and arrogant man. They are embarrassed and ashamed of themselves for being taken in by him, and they realize that they should not have blindly trusted him.
The story of "Mr. Know-All" is a cautionary tale about the dangers of being too trusting and the importance of questioning authority and seeking out the truth for oneself. It serves as a reminder that not everyone who claims to be an expert is actually knowledgeable and trustworthy, and that we should be careful not to blindly follow those who present themselves as such.