Alexander Yuryevich Sanfirov (pen name of Alexander Yuryevich Saparov) is a prominent contemporary Russian science fiction and fantasy author, widely recognized in digital libraries like Flibusta and LitRes for his contributions to the "popadantsy" (time-travel/alternate history) genre.

: Leveraging his professional background, Sanfirov details the challenges of practicing medicine with limited historical tools, making "medical procedural" fantasy a staple of his bibliography.

Sanfirov’s work is primarily defined by the genre. His protagonists are often modern professionals (frequently doctors) who are transported back in time—usually to the Soviet era or late Imperial Russia. Key characteristics of his writing include: