The Bat-Signal is a spotlight marked with Batman's insignia on top of the GCPD 9th Precinct in Gotham City. It is used by the Gotham City Police Department to call upon Batman should they ever need him.
Batman provided the signal to newly promoted Police Commissioner Gordon as a symbol of trust and a way they could communicate with each other without skulduggery.
To protect the Gotham City Police Department from summoning a costumed vigilante, as, although he encouraged the criminals to think he was working for the Police, Batman was not a deputized officer of the law, no representative of the police was allowed to access the signal. Instead the G.C.P.D. employed a civilian aide to handle the light.
- The Bat-signal first appeared in Detective Comics #60 (February, 1942)
- Through the years various people have accessed the signal, each for his or her own reasons, even criminals have used it to summon Batman's protection- although they turned the bat-symbol upside down, imitating the international symbol for distress.
Batsignal DC Database