Hello NHTom!
With the four pots You can dial in a year You would like to travel to. One of the switches sets "A.D." or "B.C.". Then, pluck a string and You are there. :D
Seriously...
These instruments have low-impedance pickups for exceptional tonal clarity. They either have separate output jacks for low-impedance mode - which allows the guitar to be directly connected to recording board or it's own amplifier, and for high-impedance mode, through which they can be connected to regular amp, or they have one output jack and a slide selector for the modes.
The pots are: Master Volume, Treble, Bass (I guess, no explanation needed), and an 11-position Decade rotary selector which varies the frequency cut of a filter. With this selector You can make the guitar sound single-coilish, or humbucker-like, even, almost like an acoustic guitar.
They also have switch for out-of-phase setting. This only operates when both pickups are on. It gives the guitar a quacky, hollow tone.
The 3-position bigger switch bypasses the Treble/Bass controls, and/or other sections of circuit.
Cheers... Bence