Which J.K. Rowling novel introduces the Hogwarts house called Slytherin?

Harry Potter and the Philosopher’s Stone introduces the Hogwarts house called Slytherin.

The first novel presents Hogwarts’ four houses during Harry’s Sorting Ceremony: Gryffindor, Hufflepuff, Ravenclaw, and Slytherin. The Sorting Hat places students according to a mixture of qualities, potential, and sometimes personal preference. Harry is considered for Slytherin before asking to be placed elsewhere.

Slytherin was founded by Salazar Slytherin, one of Hogwarts’ four founders. The house is associated with ambition, resourcefulness, determination, and cunning. Its reputation is also shaped by the large number of dark witches and wizards who belonged to it, including Tom Riddle, who later became Lord Voldemort.

The house first appears in the opening book, although later novels add important history about its founder, symbols, and connections to the plot. “Slytherin” is therefore not introduced for the first time in Chamber of Secrets, even though that book develops its hidden legacy.