All of the different authors themselves of the books must be important to average citizens because of the power they have to publish books in the first place through companies' permission and the experience they had to make it. If not all, then which are powerful through their reputation as individuals and as for the credit for the books they made?
The author of "Real Barenziah" created them as a kind of "harlequin romance" pulp fiction novel, but was nearly executed, (and WAS executed, at least on paper.). he now serves the queen under a new name, IIRC.
The anticipated disparity between well to do and commoner in terms of literacy does not seem to exist in mainland cyrrodiil, and so a thriving publishing system apparently is in sway.