Mystery of Love

Mystery of Love was written and performed by Stevens and produced by Thomas Bartlett. Luca Guadagnino asked him to act as a narrator for Call Me by Your Name. Stevens declined that role and agreed to write a song instead, with full creative control, then offered two, Mystery of Love and Visions of Gideon. He has said it was written in Oregon while he was touring Carrie & Lowell, and it names the Rogue River. The birds in its lyrics, he said, stand for absolute freedom and transcendence.

It was released digitally on 1 December 2017 under license to Madison Gate Records and Sony Classical, with a video on Pitchfork's YouTube channel on 4 January 2018. A limited Record Store Day 10-inch of 10,000 copies paired it with Visions of Gideon and the Doveman remix of Futile Devices. It was nominated for the Academy Award for Best Original Song, his first nomination in the category, and he performed it at the ceremony on 4 March 2018 with Chris Thile, Moses Sumney and St. Vincent. It also received a Grammy nomination for Best Song Written for Visual Media, his first, and won the David di Donatello for Best Original Song in March 2019. In the United States it debuted at 47 on Billboard's Hot Rock and Alternative Songs chart and later reached 13. An early demo was released in March 2025 to announce the Carrie & Lowell anniversary edition.