Do you have the most recent game version? Version 20.03.30?
Or did you perhaps use update files but skipped an update?
Does the book not work for you in general or is just the option for Moriko not in it?
i have Version 20.03.30, i dident use update files i downloaded the entire game since i was a while since i played last, and i can use the book but all the option i see are
"Change text speed"
"Toggle auto saving"
"Toggle all-kill attack"
"Reduce party level"
"Reset Millwater murder events"
"Reset Lace's events"
in that order