The Blue Pearl is a small, beautifully bound volume of Essi Daven's collected ballads. During her stay at the Temple of Melitele, under the tutelage of Yennefer, Ciri became quite a voracious reader. This was one of her favourite books.
The name of this book "The Blue Pearl" is from a small jewel that Geralt gives to Essi in the short story "Trochę poświęcenia" ("A Little Sacrifice") as her birthday present. It was in fact a blue pearl. She never separates herself from this gift. In fact, she is still found wearing the necklace when Dandelion buries her body along with her lute.