Pete Rugolo, who had worked on David Janssen's earlier series "Richard Diamond, Private Detective", composed the original music for "The Fugitive". (Rugolo would later work with creator Roy Huggins on "Run for Your Life" and other projects.) Tracking music was standard practice at the time, but unlike virtually all primetime scripted series of the 1960s, no episode – not even "The Judgment" – received an original score; all the original music used for the series was composed by Rugolo and recorded in London before the series was filmed. In fact, many episodes had Rugolo as the sole credited composer for the episode's scores. However, only a fraction of all the music heard throughout the series was original Rugolo music. Library music (either from other classic TV shows or from stock music libraries, as was the case with "The Adventures of Superman") provided a majority of the episodes' scores. For example, Dominic Frontiere cues became common in the season four; a keen listener could find himself listening to such cues from the "Outer Limits" series during the climactic final episode of "The Fugitive." Numerous ominous, dramatic and suspenseful cues from "The Twilight Zone" episodes such as "The Invaders", among others are used to strong effect throughout the series. The old pop songs "I'll Never Smile Again" and "I'll Remember April" each appear several times in the series, often associated with Kimble's deceased wife, Helen.