How does a dielectric increase maximum electric field strength?

[needingtoknow]

Homework Statement

How does a dielectric increase maximum electric field strength?

From the two cases where a dielectric is inserted into a charged capacitor after it is disconnected and after it is remained connected it seems that E will either decrease or stay the same. But I read in just a few pages later that "The presence of a dielectric increases this maximum electric field strength" and I was confused as it contradicts the two cases of inserting a dielectric in which electric field strength would either decrease or stay the same.

 

[Simon Bridge]

Context is important.
You need to check what the book is calling "maximum electric field strength".

I suspect sloppy wording.