RSHA - aside from the obvious, what was it ?

[WaistGunner]

I see loads of folk discussing the RSHA and its officers, I know it was the Nazi Security HQ, but what was it ? How was it organised ? Who did what ? Was it the same as SD - Hauptamt ?

This is a bit of my usual track but you guys just gotten me wondering.

[Georges JEROME]

RSHA was created in 1939 with
party office SD (intelligence office of SS)
and
governement office SIPO (security police)

AMT I and II were administrative offices
AMT III was SD inland (intelligence inside germany)
AMT IV was gestapo (political police)
AMT V was Kripo (criminal police )
AMT VI was SD Ausland (foreign intelligence)
AMT VII was a research office