Mesh invissible in object mode and can't be edited

TLDR; ‘/’ on the numpad fixes problem

Building a ship with 5 meshes. I come out of editing the superstructure mesh and suddenly everything else is invisible, including the light and camera.

Alt-H does nothing
Objects are set to show up in outliner
Not a face problem
No importing, everything scratch built
I don’t think its a layer problem, but I might be wrong, as I’m a little fuzzy on those.
Oddly enough pressing F12 only renders the visible mesh, but pressing it again renders the invisible meshes as well

I assume I’ve inadvertently I’ve inadvertently hit a keyboard shortcut that technically does something really clever, but which is rather confusing if you don’t know about it. Anyone any ideas?

As a separate question, is there any way to get blender to show all the commands you’ve given it over a period of time? Problems like this might be easier to self-diagnose if I could go back through the list and look for things I don’t recognise.

Edit: This is the file that’s giving me problems. IT_03; upper hulla.blend (567 KB)

See if you are in so called Local View - should be written on 3d view upper left corner - (Local). Numpad ‘/’ switches on, off.
You can see some of your actions in Info window: pull down upper menu line a bit. Not all keystrokes will be there though.
Undo History on Toolshelf should have listed more.

Numpad / does not solve problem. Useful shortcut though. I’ve added a copy of the origonal file to the OP.

This is really driving me up the wall as now it’s happened for the second time in two days. Same as before. Meshes are listed but will not display in Object mode, and cannot be edited. As a related problem, I now have another mesh that shows up in object mode, but can only be selected in outliner, and can be edited.

I’m pretty sure it is a command and not a glitch, as this has happened before across multiple versions of blender, as well as the fresh install (2.75A 64bit windwos) I’m running.

Erm… Can’t see it…?

EDIT: Ah! There it is.

Try it now.

This is what I see when I open your file:

You are in local view, exactly as eppo predicted.
Numpad-/ solves the issue for me. Make sure you are over the 3D viewport with the mouse cursor when hitting that key: Blender’s keyboard shortcuts are extremely context sensitive.

I could have sworn that didn’t work earlier when I tried it. And now it does. Well don’t I feel foolish now.

Thank you both for your help and patience.