The linking books are inside the rotating domes, PJones. If they are not active, that means that you have not yet gotten power to them. Unfortunately, that means another trip to the fire marble puzzle in the upper gold dome.
After you set the marbles (all but yellow) and lower the plate over the grid (leave it in place), there is a little white button on the wall that you must push. If you placed the marbles correctly, you'll see and hear the power surge (like a mini explosion). Then you should be able to access the linking book in any of the rotating domes. Good luck!
The shortest period of time lies between the minute you put some money away for a rainy day and the unexpected arrival of rain.
~Jane Bryant Quinn