"Co víš o té knize?"

[PedroMarquez13]

is viš here the verb to see, used as to know?

[BoneheadBass]

The verb is actually vědět, which does mean "to know." Víš is the second person singular form. "To see" is vidět, with vidíš for second person singular.

[PedroMarquez13]

oh nice, thank you!