In a nutshell, the author recommends checking your email manually when YOU are ready to deal with it - and not have a constant flow of email interruptions throughout the day. A novel idea in this era of always on/instant delivery corporate email systems.
Also, some other good thoughts on scheduling uninterrupted work.
I've started implementing his email suggestions today and so far, so good. I don't miss that little sound and icon popping up while I'm in the middle of something.
"Simplicity is the ultimate sophistication."
-- Leonardo da Vinci