This fascination with the past—particularly a past that one hasn’t experienced—has become a central theme in the work of Jamie Smith, the twenty-six-year-old producer and d.j. who goes by the name Jamie xx. Smith first rose to prominence, around 2009, as a member of the xx, a London-based band that includes the singer and guitarist Romy Madley Croft and the singer and bassist Oliver Sim. The three friends met in primary school, and they honed their sound by quietly rehearsing at night, in their bedrooms, conscious of the fact that their families were trying to sleep. (A fourth member, Baria Qureshi, was asked to leave the band early on.) Fittingly, the xx’s two albums are intimate and gorgeous, driven by dreamy, whispery duets and Madley Croft’s spangled, searching guitar lines. The group’s best work can feel like monumental pop songs rendered in miniature. Their self-titled début album won the 2010 Mercury Prize.