"A Court of Frost and Starlight" is a novella written by Sarah J. Maas and is part of the "A Court of Thorns and Roses" series. The series is known for its blend of fantasy, romance, and adventure and has garnered a substantial following among young adult and fantasy literature enthusiasts.

Published in 2018, "A Court of Frost and Starlight" serves as a bridge between the events of the third book, "A Court of Wings and Ruin," and the upcoming novels in the series. It takes place in the aftermath of a war that has significantly impacted the world and characters introduced in the earlier books. In this novella, readers get a chance to delve deeper into the lives and relationships of the central characters, particularly Feyre Archeron and Rhysand, as they navigate the challenges of rebuilding their world and dealing with the emotional aftermath of the conflict.

The novella also provides readers with insight into the lives and experiences of other characters from the series, offering a more intimate and character-driven exploration compared to the high-stakes action of the main novels.

While "A Court of Frost and Starlight" is generally well-received by fans of the series for its character development and glimpses into the characters' lives, it has also faced some controversy and criticism. Some readers have found fault with certain aspects of the story, including its pacing and the handling of certain character arcs.