Days with Dr. Yen Lo is a full-length studio rap album by the duo Dr. Yen – Ka and DJ Preservation. The pair recorded the album at The End in Greenpoint, Brooklyn, New York, where it was released on May 16, 2015 via Pavlov Institute Records. The album was produced by Preservation with Tim Fodness as co-producer. The group's name, as well as the album title, were inspired by Khigh Dhiegh's character Dr. Yen Lo from John Frankenheimer's 1962 film The Manchurian Candidate. The album was Ka's fourth studio album, following 2013s The Night's Gambit and preceding Honor Killed the Samurai released in 2016. The duo had previously collaborated together on 1200 B.C. an extended play released in 2014. The trailer for the album was released on February 12, 2015 via Ka's YouTube channel. The album features 12 tracks, all named "Day" followed by a number. A series of music videos were released for three of the tracks:"Day 0", "Day 3" and "Day 70", all directed by the duo.