Vertigo is an imprint of DC Comics for mature readers and is a continuity separate from the DC Universe that includes Sandman, Swamp Thing, John Constantine (Hellblazer) and others.
Pre-Vertigo and Its Birth
In the early 90's, DC Comics was publishing a volume known as the " Who's Who in the DC Universe" encyclopedia. Many of the issues contained a common theme and one of the final issues, #15 (cover date of January '92, just a year before Vertigo came into existence) was labeled with the theme "DC's Realm of Dark Fantasy". Many of the characters in the issue were being written in continuing series by DC at the time, but were later given to Vertigo who either continued the series (Hellblazer, The Sandman, Doom Patrol, The Saga of the Swamp Thing, Shade the Changing Man) or made their own later on and published a collected trade of DC's series (Black Orchid, Kid Eternity).
So it was that these pioneer titles birthed the concept of an imprint covering the darker elements DC had been publishing, and the more adult comics (such as DC's numerous horror comics of the mid-1900's), many of which were re-made into Vertigo miniseries years later.
The Titles that Started It All
On January 13 of 1993, Vertigo was finally born...and so several of the darker titles DC was currently printing were given the imprint label on their covers, the first issues in these series to possess the Vertigo label are as follows (all of them are cover dated March 1993).
Death: The High Cost of Living #1 (ended with 3)
Enigma #1 (ended with 8)
Shade, the Changing Man #33 (ended with 70)
The Sandman #47 (ended with 75)
Animal Man #57 (ended with 89)
Hellblazer #63 (still ongoing)
Doom Patrol #64 (ended with 87)
Swamp Thing #129 (ended with 171)
Of these series, only The Sandman has ever been fully reprinted by Vertigo with the others only partially collected.
Vertigo or DC?
Also, with the publisher label on the covers of Vertigo comics, it actually took a few years for a cover to simply say "Vertigo" as for the beginning years it would always read Vertigo, and either below/above it DC. It wasn't until late 2002 just before the Vertigo X (representing Vertigo's tenth anniversary) started appearing on covers that DC finally removed its logo from the Vertigo covers.
The picture on the right displays many of the adult characters from DC Comics, but not all of them have appeared in Vertigo and some have appeared in both DC and Vertigo, proving that their is no clear-cut definition between DC and Vertigo.
Conflicting Publishers
Another key thing to remember about Vertigo is quite a few of the comics they publish (usually in graphic novel form) were originally owned by another publisher, whether a small "no-name" one or DC, or even a thrown-away former DC imprint. Also, several of Vertigo's longest running series actually began as DC comics before the Vertigo imprint was released.
Subimprints
Vertigo Visions Vertigo Voices
Vertigo Verite
V2K
Vertigo Crime
Vertigo's Longest-Running Volumes from Largest to Smallest
Vertigo mainly publishes graphic novels and miniseries so here is a list of all its series that have surpassed fifty issues:
Hellblazer (1988-X)
the only currently ongoing Vertigo series that began before the imprint existed
Last Issue: 259
Swamp Thing (1982-1996)the only Swamp Thing volume to surpass twenty-nine issues
Last Issue: 171
100 Bullets (1999-2009)the longest-running series to have started under the Vertigo imprint and not DC
Last Issue: 100
Last Issue: 89
Doom Patrol (1987-1995)Last Issue: 87
Fables (2002-X)Last Issue: 88
Lucifer (2000-2006)Last Issue: 75
The Books of Magic (1994-2000)Last Issue: 75
The Sandman (1989-1996)Last Issue: 75
Sandman Mystery Theatre (1993-1999)Last Issue: 70
Shade, the Changing Man (1990-1996)Last Issue: 70
Preacher (1995-2000)Last Issue: 66
Y: The Last Man (2002-2008)Last Issue: 60
Transmetropolitan (1997-2002)Last Issue: 60
The Dreaming (1996-2001)Last Issue: 60
The Invisibles (1994-1996)/ The Invisibles (1997-1999)/ The Invisibles (1999-1999)
Last Issue: 25/22/12 (59)
