Robert Louis Stevenson significantly influenced the adventure and horror literary genres. His novels, such as Treasure Island and Strange Case of Dr Jekyll and Mr Hyde, set new standards in storytelling. Treasure Island introduced the archetypal pirate adventure, pioneering themes of treasure hunting and moral ambiguity. Meanwhile, Jekyll and Hyde delved into the complexities of human duality, shaping modern horror literature. Stevenson's knack for creating suspenseful narratives and vivid characters captivated readers, allowing him to explore psychological themes. His innovative storytelling has left a lasting legacy that resonates within both genres today.