I've recently been re-reading the book Beyond Forcing Moves. I first read it when I was around 10k and don't remember much about it: I think it was rather advanced for me then. Now I'm 3 dan and have found it excellent (apart form the pagination mistake!) and full of nice examples of good kikashi technique.
I'm thanking this book because it was largely down to the chapter about the peep of
below that I won my recent game in the European Team Championships. I won't go over all the variations here (buy the book!) but the key point is white needs to peep here now to prevent black resisting with the counter peep at a before the stakes are higher on the side. If black can get in the counter peep and white is forced to solidly connect, then this peeping stone has a significant impact on cuts that can appear just above a. In fact in my game rather than playing 
for territory I chose b instead for influence, but I then ended up connecting under for territory due to white's choice of q11.Here's my game. My opponent peeped too late so I could resist with the counter peep and the strong move of o4 when white pushed and cut. After that he could have accepted a slightly bad local result but overplayed and just kept digging himself into a bigger hole and I had a one-way route to victory (though of course it's all too easy to lose even these sort of games!).
(tenuki is also possible, but then if black connects his stone white has many cuts), but then black has a powerful push and cut, White cannot capture this cutting stone, so might try the peep now, and if black docilely connects at a then white captures with b. But of course black won't connect, he will save his cutting stone and fight.
as white didn't defend solidly against the peep. Instead black can save his single stone making miai of p11 and p9, allowing him to cut and effectively capture 3 white stones (maybe white can save them, but they are very heavy so sacrifice is best). White then pushes and has a choice which side to cut.
for 
then a then b), connecting his corner and central stones. This is a disaster for white, who will have a hard job managing all his eyeless groups.
)-: comedy/tragedy