Guiding Light

Soap Opera that began on NBC radio on January 25, 1937. It moved to CBS radio in 1947, then to television in 1952. Originally The Guiding Light, it was shortened to Guiding Light in 1975. In April 2009, it was announced that it would end its run in September 2009 and the show indeed ended on September 18, 2009 as scheduled -- after a mind-boggling 15,762 episodes.

The single most important thing about Guiding Light is this: It may be the longest recorded narrative in the entire history of mankind. It has produced a total of about 18 continuous months' worth of narrative material (both audio and video). That is, if you listened to/watched the show, from the beginning, 24 hours a day, it would take nearly a year and a half to get through it all; for comparison, if The Simpsons wanted to break this record, it would still have to be producing new episodes in 2062. (The British soap Coronation Street pronounces itself the world's longest-lasting soap on each of its major anniversaries, but it isn't even Britain's longest-lasting soap - that honour belongs to The Archers - although it is the longest-lasting TV soap still in production... however, with just over 7000 episodes produced it has quite a way to go.)

However, this being a daytime Soap Opera, not all of this narrative material is known to exist. Not much survives from the radio years, or the first 25 years or so of its TV incarnation, and what does exist is in the form of kinescopes and home video recordings (and vinyls, in the case of the radio years).

For a more detailed look at the show's run, the Other Wiki has you covered.

Tropes used in Guiding Light include:

Artifact Title: The title referred to a lamp in the preacher's study during the radio years. Over time that plot point was dropped, but the title remained.
Becoming the Mask: In the early 90s Blake began to seduce Ross to get revenge against her mother. However she found herself falling in love and eventually they wed.
Betty and Veronica: Some examples include Josh as the Archie, with Reva and Annie, and later Olivia filling the roles of Betty and Veronica.
- Many examples, some of the most famous include Holly as Archie, Ed as Betty and Roger as Veronica.
The Cameo: Rudy Giuliani appeared as himself, while he was still mayor. (The show was filmed in New York.)
Chuck Cunningham Syndrome: Claire Ramsey, Vicky Spaulding are both examples.
Cloning Blues: The only American soap to ever use a cloning storyline, complete with a serum to make her older. She died...horribly...and was never mentioned again, by anyone.
Chronic Villainy: Reva had her moments.
A Day in the Limelight: In later years, Wednesdays became "Character Days" where the episode focused around one character instead of standard soap rotation.
Deadly Distant Finale. The last few scenes of the show take place exactly a year after the rest of the episode: showing everyone's Happily Ever After. Except Edmund and Jeffrey, who are locked in a Stern Chase with No Ending.
Enfant Terrible: Cassie's youngest son, Will. He was deliberately cast with Seamus Davey-Fitzpatrick, the child actor who played Damien in The Omen remake for this purpose.
Family Relationship Switcheroo: Philip is led to believe his biological parents are Alan and Elizabeth Spaulding. In actuality, they are Justin and Jackie Marler, his former step-parents. He finds out via Bradley, his girlfriend Beth's abusive stepfather.
Happily Ever After: The Finale does this with some last second romantic entanglements.
Hooker with a Heart of Gold: Selena Davis
Large Ham: Kim Zimmer as Reva Shayne, and never more so than in one of the show's most famous scenes.

Reva: I BAPTIZE MYSELF THE SLUT OF SPRINGFIELD!

Long Runner: Nearly Seventy-three years! As we keep mentioning, it's the longest running narrative in human history.
Love Dodecahedron
May-December Romance: Alan and Hope, HB and Reva, Roger and Dinah, Ross and Blake, Matt and Vanessa
Older Than Television: Guiding Light itself.
Put on a Bus: Rita Stapleton.
Rape and Revenge: Holly shot Roger in the chest three times after he raped her.
Series Continuity Error: Inevitable. The series ran for four full human generations of writers; no one man could ever keep decades of literally ceaseless continuity straight (the show existed before archiving was easy) and there were mistakes at times.
- Could sometimes branch into They Just Didn't Care, as the show once gave Alan Michael flashbacks of his childhood in the Spaulding mansion, - even though he was introduced as an eighteen-year-old man crashing a party to introduce himself to Alan.
Soap Opera: To this day, the copyrights and trademarks to the show's characters are still owned by Proctor & Gamble
Soap Opera Disease
Soap Opera Rapid Aging Syndrome:
- To ridiculous extents. One character was SORASed so she was twelve years older than her older brother.
- Phillip Spaulding is an infamous example, he went from six months old to about seventeen years in a matter of months.
Sound to Screen Adaptation
The Three Certainties in Life:

Lizzie Spaulding: Love isn't a sure thing. Granddad, on the other hand, is right up there with death and taxes.

Toilet Seat Divorce: Many have taken place in Springfield, but Josh and Reva are notable for doing this a lot.
Where the Hell Is Springfield?: The show is actually set in a town named Springfield. It was originally of this trope, but then decided it was Springfield, Illinois.
Wicked Cultured: Roger Thorpe.