out of "intensive care".
Mildew can also be a deciding factor whether the "patient" lives or dies.There are many types of mildew and all are commonly known as "Foxing", the mildew gets its name from the (F)errous (Ox)ide or the iron it is attracted to in the paper, usually chemical wood pulp, and all are activated by the same cause...relative humidity.

This is a mild case affecting mainly around the edges.
Whereas the severety of this case is pretty much beyond belief!!!... but this "Book Doctor" has spent the past 30 years developing and implementing unique formulae for every kind of book restoration......................successfully.