Try a solution of borax - one cup of borax in a gallon of water. Dampen a shammy with it and wipe each page of the book, then allow the page to dry. Then go on to the next page. This is a slow process.
To clean the area -
First vacuum the area with a HEPA vacuum cleaner.
Clean the area with the borax solution and a brush.
Wipe the area with a shammy dampened with the solution.
Allow to dry
Borax is a mold inhibitor - this should prevent the mold from coming back.
And, incidentally, adding borax to white glue turns it into this wonderful goop....
The Auld Grump.