Welcome to Which three books?

I was watching the 1960 movie version of The Time Machine, starring Rod Taylor (I only discovered there was a 2002 version when looking this up.).
When I later read the book, I realised that the adaptation was better than H.G. Wells' original text in at least one area, though I thought in close up that the Morlocks looked seriously poor.

Right at the end, David Filby (Alan Young) ponders:

FILBY
But it isn't like George. - To return empty handed. To try to rebuild a civilization without a plan.
(to Mrs. Watchett)
He must have taken something with him.

MRS. WATCHETT
Nothing.

She looks around and discovers three empty spaces on the tightly packed book shelves. She walks to them.

MRS. WATCHETT
Nothing except three books.

FILBY
Which three books?

MRS. WATCHETT
I don't know. -- Is it important?

FILBY (smiles)
No, I suppose not. - Only...what three books would you have taken?

[From Screenplays for You]

Now, I'm struck with how little it would take to turn a lot of people in the U.K. into Eloi. But that's another blog!

Here, I want to ask people which three books they would take on a trip they might not return from. I'll be trying out podcasting for the first time so I hope it will work rather than know it will.

And yes, I'm assuming that there's no Internet coverage on the trip.

Comments and suggestions welcome.