I started Myst V for the first time in years (after the sale at GOG). I got through Toldemer (?) and now I'm in Noloben. I feel foolish, but I've misplaced my tablet.
I think I left it in the tunnel when I went back up the ladder, but now I can't find it. It's not back in the bubble, or on the pedestal I finally got to.
On Noloben, the Bahro won't enter the tunnels or Esher's laboratory (they are afraid of the snakes that roam there). So if you leave the tablet anywhere in those areas, it will remain untouched until you go find it again.
Thanks, Ainia--I remembered that (as I had just been lectured by Esher). That's why I was so puzzled... I never did remember where I left it. Fortunately, when I quit and re-entered the game, I had my tablet again! Two down, two to go...