The Baudelaire orphans:
* Violet Baudelaire: The eldest, a brilliant inventor with a talent for creating contraptions.
* Klaus Baudelaire: The middle child, a voracious reader and expert on a wide range of subjects.
* Sunny Baudelaire: The youngest, a baby who communicates through a unique baby language and has surprisingly sharp teeth.
Adults:
* Count Olaf: The main antagonist, a villainous, greedy actor who is obsessed with inheriting the Baudelaire fortune.
* Mr. Poe: The Baudelaire children's inept and unhelpful guardian, who repeatedly places them in dangerous situations.
* Justice Strauss: The children's kind and intelligent librarian, who is unfortunately not able to provide them with permanent shelter.
* Aunt Josephine: An elderly woman who is extremely afraid of everything.
* Esme Squalor: A wealthy and eccentric woman who is married to Count Olaf.
Other characters:
* The Baudelaires' parents: They are only mentioned, never seen. It is suggested they were killed in a fire.
* The Quagmire triplets: Three friends of the Baudelaires who also face Count Olaf's machinations.
* The "Theses": A secret society who seems to be connected to the Baudelaires' past.
This is just a brief introduction, as the book, and the entire series, are full of colorful and interesting characters, both good and bad. The author, Lemony Snicket (a pseudonym for Daniel Handler), uses these characters to weave a complex and captivating story filled with intrigue, danger, and a touch of humor.