I'm sure Don sent it to Rachel. It fits with their final conversation.

Would be a kick though if he'd sent it to Betty.

You mean the choice of that book itself? I'm not sure, other than to show how much of the beat poetry/thought was moving more into the mainstream and setting the groundwork for the big philosophical/societal changes on the horizon. And to show how much Don's world is about to change. Yet at the same time, he too wants more and doesn't know how to find it (remember when he told Roger how he wasn't going to be in advertising forever...he too doesn't quite know who he is or what his "destiny" is. Therefore, he too needs a few meditations in his existential emergency.

Ken,
Since he had just gotten back from a physical and the doctor told him to take it easy. We see Don wanting not to push so hard and perhaps meditating. But, according to someone's past blogs who looked up this book, it's a book of poetry!
Regertz,
It would be a kick if he sent it to Betty, but don't think so.

I also think he sent it to Rachel.

I'm sure it was an attempt to show the "counter cultures" inclusion into mainstream America, but I think they could have used Kerouac,Burroughs,Ginsberg,etc. just as well. I checked out OHaras collection of poetry and that particular book seems to center alot on NYC at the time so perhaps it's also that juxtaposition of "mainstream" vs. the beat culture that's intriguing to the Madison Avenue types. Anyway, this show is absolutely amazing!!! Hey Nora, I've seen alot of posts by you, whats your invovlement here?

Frank O'Hara wasn't a "beat" poet. He was of The New York school, along with John Ashbery, Kenneth Koch, and James Schuyler. The guy who runs The Best American Poetry blog wrote a book about them and he watches MM.
http://thebestamericanpoetry.typepad.com/the_best_american_poetry/television/