Instrumental themes have long been effective in anchoring programs to particular aesthetic and cultural sensibilities. For example, Henry Mancini's smoky, driving Peter Gunn theme is still an evocative take on the postwar private eye. Similarly, a few years later, Laurie Johnson's jaunty theme for The Avengers effectively captured that series' signature cocktail of sex, wit, and derring-do, while Lalo Schifrin's blazingly minimalist Mission: Impossible theme became one of the most recognizable themes of all time. Other hailed instrumentals include the themes to The Twilight Zone and The X-Files, which eerily suggest the fear of the unknown; the themes to Doctor Kildare and St. Elsewhere, which calmly indicate melodrama and care; and the themes to The Andy Griffith Show and Northern Exposure, which convey a laid-back, rural sensibility.

     Instrumental themes also mark significant changes in genre. The themes of 1950s police series such as Dragnet and Highway Patrol emphasized a martial, no-nonsense "law and order" mood. However, police series of the 1970s, such as Hawaii Five-O or S.W.A.T., generally featured hard, brassy themes that promised gritty urban action, while recent  themes  have  been more brooding than ballistic, reflecting their series• contemplative moods (for instance, Homicide: Life On The Streets and NYPD  Blue).  Instrumental  sitcom themes have ranged over an even greater  terrain,  tak­ing in bouncy and childlike (Leave It To Beaver); sub­urban and swinging (The Dick Van Dyke Show); urban and funky (Sanford And Son); sensitive  and  melancholic (Taxi); easygoing and jazzy (The Cosby Show); bluesy and working class (Roseanne); and ironic and chaotic (The Simpsons), among many other moods.

     Theme songs with lyrics convey a more intimate expression of a series' context, as their explicit declarations match their protagonists' depicted social and emotional aspirations. Accordingly, such themes are often heard in post-1970 sitcoms, which generally focus on their characters' quests for community and emotional security, such as Alice, All In The Family. Dijf 'rent Strokes, Friends, The Golden Girls, Good Times, Laverne & Shirley: Malcolm In The  Middle, The Mary Tyler Moore Show, One Day At A Time, Scrubs, Welcome Back, Kotter, and WKRP In Cincinnati. In the case of All In The Family, the theme was even performed on camera by two of its main characters (Archie and Edith Bunker) in every episode, vividly depicting their perspectives.

     Occasionally. sitcom lyrics even provide a detailed exposition of a program's basic situation. This trend was heard most famously in the themes to 1960s and 1970s series such as The Beverly Hillbillies, The Brady Bunch, F Troop, Gilligan's Island, Green Acres, and The Patty Duke Show. Such themes were archly resurrected in a few 1990s sitcoms (such as Fresh Prince of Bel-Air, Hennan's Head, and The Nanny, which managed to rhyme "crushing scenes" with "Flushing, Queens").

     Existing compositions have also often become popular television theme songs. Charles Gounod's "Funeral March of the Marionettes" is probably better known as the theme to Alfred Hitchcock Presents, while John Philip Sousa's "Liberty Bell March" now has a similar connotation thanks to its use on Monty Python's Flying Circus. Seventeenth century composer Jean-Joseph Mouret's Rondeau from Symphonies and Fanfares for the King's Supper still serves as the fanfare to Masterpiece Theatre. The original hit recording of "Rock Around The Clock" (performed by Bill Haley and the Comets) appropriately opened each episode of Happy Days during its first two seasons (complete with a juke­ box motif, with the song starting as the needle hit the record), before being replaced with an original, eponymous song. A languid instrumental of "Georgia On My Mind" was used as the theme for the Atlanta-set Designing Women until its last season, when Ray Charles appeared in the credits (with the cast draping his piano), to sing the song. More recent uses of existing songs include: Carole King's "Where You Lead, I Will Follow" (from her popular 1970 album Tapestry), which was re-recorded as a duet between King and her daughter Louise Goffin to evoke the mother-daughter sentiments of Gilmore Girls; The Who's "Who Are You?," which graces CSI: Crime Scene Investigation for its rock ethos, familiarity with the target audience, and lyrical confluence with the series' subject matter; and Diane Warren's soft-rock ballad "Where My Heart Will Take Me," which bombastically connects the spacefarers of Star Trek: Enterprise to sentimental longing.

     Although well-conceived television theme songs become popular and recognizable with viewers, they have only rarely become full-fledged pop hits with listeners, in terms of radio airplay and sales. Jan Ham­ mer's Miami Vice theme, released as a single in 1985, is still the all-time best-selling television theme song; other notable hits include the themes from The Greatest American Hero, S.W:A.T., and Welcome Back, Kot­ter. Beyond the theme song, entire soundtrack albums have been released featuring music heard in (or "inspired by") particular series . This practice began in the 1950s with the likes of Mancini's Mr. Lucky and Peter Gunn albums, but continues to this day. Some soundtrack releases are collections of incidental music (e.g. Star Trek, The Twilight Zone, Xena: Warrior Princess), while others are compilations of pop songs that are featured in their respective programs (e.g. Beverly Hills 902/0, Friends, The Heights, Smallville).