Length of a Dissertation Summary for a Postdoc job
Why does typical matter? You have three pages. You may need it or not. 

Don't say more than you need to, but give an explanation that the readers can relate to. 

My dissertation, which was very involved and quite long could be described (to an expert) in a couple of paragraphs - and they would have been impressed. But other topics would take more explanation than mine did in mathematics.

But, as they imply you may have more to say about other recent scholarly matters - work in progress, for example.