Is the Engine open source?

[HarbingerOfLive]

I mean I heard a while ago that I could be able to use this engine to my liking to make things like maps and stuff. I want to know is there a open sourced version of this engine to make maps and various things?

[Som1Lse]

HPL1 is, which is the engine powering the Penumbra series.
HPL2 isn't, which is the engine powering Amnesia.

[Sexbad]

What Someone else said, except you don't need the source code to make mods.

You can find the tools here, along with some sexy tutorials and stuff: http://wiki.frictionalgames.com/hpl2/start
They are currently available for Windows and Linux, but not Mac.