Here's how:
* Themes of ambition and the dangers of knowledge: Shelley's poetry, particularly works like "Prometheus Unbound," explored the themes of ambition, the thirst for knowledge, and the consequences of exceeding human limitations. These themes are central to *Frankenstein*, where Victor Frankenstein's ambition for scientific achievement ultimately leads to tragedy.
* The Romantic sensibility: Shelley's poetry was steeped in Romanticism, with its focus on individual experience, the power of nature, and the exploration of emotions. These elements are also present in *Frankenstein*, where Mary explores the emotional turmoil of Victor and the creature, and the role of nature in shaping their experiences.
* The Gothic tradition: Shelley's poetry often employed Gothic elements, such as dark and mysterious settings, supernatural themes, and the exploration of the macabre. This gothic sensibility is a significant aspect of *Frankenstein*, contributing to the novel's suspenseful atmosphere and unsettling themes.
While Percy Shelley did not directly influence the writing of *Frankenstein*, his work, his ideas, and the intellectual atmosphere he helped cultivate certainly played a role in shaping Mary Shelley's literary sensibilities and the themes she explored in her masterpiece.
It is worth noting that Mary Shelley also engaged with other literary and philosophical ideas, including those of John Milton's *Paradise Lost* and Jean-Jacques Rousseau's theories on human nature, which contributed to her development of *Frankenstein*.