Kerstin Gier

In the world of time-traveling teens, hidden diaries, and secret societies, Kerstin Gier has carved out a space that feels both whimsical and wise. Best known for her Ruby Red Trilogy, Gier blends fantasy with romantic tension and just the right dose of humor—making her stories irresistible to young adult readers around the globe. Her gift lies not in epic battles or sprawling world-building, but in creating tightly woven tales where time travel feels like an emotional journey as much as a physical one.

Born in the German town of Bergisch Gladbach, Gier didn’t always dream of being a writer. She studied education and psychology before finding her voice in fiction, first writing adult comedies under various pen names. But it was her pivot to young adult fantasy that brought her international acclaim. Ruby Red (Rubinrot), originally written in German, became a bestseller not only in her home country but also found devoted fans in English-speaking countries and beyond—thanks in part to its clever blend of historical intrigue and relatable teenage confusion.