That is actually the title of a classic detective novel by Raymond Chandler, but the long and short of it is that there are a number of ways to say goodbye in German – some of them longer than others! Let's start with what you probably already know:

Ja, damit sind wir fertig. Auf Wiedersehen!

Yes, with that we are finished. Goodbye!

Caption 77, Das 1. Newtonsche Gesetz - erklärt am Beispiel des Dodomobils

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BANNER PLACEHOLDER

Ich sehe Sie dann morgen. Auf Wiederhören.

I'll see you tomorrow then. Goodbye.

Caption 52, Berufsleben - das Vorstellungsgespräch

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Because of the -sehen in Wiedersehen ("see you again") and -hören in Wiederhören ("hear from you again"), auf Wiederhören is the proper form to use on the telephone.

Wiedersehen, vielen Dank! -Tschüss. -Tschüss.

Goodbye, many thanks! -Bye. -Bye.

Caption 25, Großstadtrevier - Von Monstern und Mördern

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Tschüss is an informal waym of saying goodbye that originally stems from the Spanish word for goodbye, adios.

Bis morgen. Ciao.

See you tomorrow. Ciao.

Caption 40, Bäppi im Fernsehstudio - Bäppis best model by Hilde Klump

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"Ciao" is actually from the Italian and can, depending upon the context, be used for hello or goodbye. It is not even translated as "bye" here as it has been adopted into English by most American and British dictionaries. It's usage in German is very informal.

Sie wissen schon, was wir meinen. Adieu.

You do know what we mean. Adieu.

Captions 64-65, Die Pfefferkörner - Endspurt

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The French word for goodbye, adieu, has also been adopted by English and is thus generally not translated.

Ich hab was vergessen. -Aha. -Wir sehen uns.

I forgot something. -Aha. -See you.

Caption 66, Die Pfefferkörner - Eigentor

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It is also common to say Wir sehen uns morgen ("We'll see each other tomorrow" or "See you tomorrow"), or Wir sehen uns wieder ("We'll see each other again"), and so forth. It sounds a bit impersonal to the ears of an English speaker, but you can also say man sieht sich, which translates as "We'll see each other" or simply "See you." 

Mir hat's super gefallen. Bis dann!

I really enjoyed it. Until then!

Caption 93, Frisbee - Karlsruher Weihnachtsturnier

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Hast du die Mathehausaufgaben denn schon fertig? -Ja, bis später.

Have you finished the math homework already? -Yes, see you later.

Caption 2, Knallerfrauen - Mathehausaufgaben

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Mach's gut, Herbert. Bis bald.

Take care, Herbert. See you soon.

Caption 4, Nicos Weg - A1 Folge 3: Tschüss!

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Bis zum nächsten Mal.

Until next time.

Caption 21, Berlin - Domäne Dahlem

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Many of the ways to say goodbye using bis and some point in the future may be translated, depending upon the context, as either "till," "until," or "see you..." So if somebody says bis morgen, you could translate it as "till tomorrow," "until tomorrow," or "see you tomorrow."

Note that macht's gut, which could be literally translated as "fare well" or "farewell," is used as an informal way to say goodbye in some German regional dialects. Another good equivalent translation could be "have a good one."

But how do you say "to say goodbye" as in "to take leave" of somebody? The most common ways are Abschied nehmen and the reflexive verb sich verabschieden:

Aber als Flüchtling muss man eben oft Abschied nehmen.

But as a refugee, you often have to say goodbye.

Caption 35, Filmtrailer - Als Hitler das rosa Kaninchen stahl

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Und hier verabschieden wir uns auch von euch.

And we will say goodbye to you here.

Caption 39, 48 h in Innsbruck - Sehenswürdigkeiten & Tipps

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Further Learning
I hope that learning about goodbye didn't take too long—this is a lesson and not a novel, after all! Look for some of the ways of saying goodbye on Yabla German, and take special note of how some are used in formal contexts and others in more casual situations. So until next time, mach's gut and stay healthy!