Even a cursory, glancing look at our Sedra is enough to see that something very unusual, not found anywhere else in the Torah, occurs here: There are 2 upside-down letters surrounding two very famous p'sukim:

"Vay'hi bin'so'a ha'aron: When the Ark traveled, Moshe said: "Arise, G-d, & scatter Your enemies. And when the Ark rested, he would say: "Return, G-d, the tens of thousands of Israel."

Why would these sentences be framed by 2 extraneous letters? And why are those letters davka the letter Nun?

The Gemara in Shabbat says the floating letters indicate that this small section is out of order, not in its proper place. OK, but then why is it out of place? In another opinion, Rebbi (Rav Yehuda HaNasi) postulates that this section is framed because it constitutes a completely separate book of the Torah! What does that mean?

Let's try to make some sense of it all. The S'forno (as elucidated by Rav Soloveichek) explains that, at this juncture in our history, we were primed to enter Eretz Yisrael. We had achieved physical freedom, received the Torah & built the Mishkan; the Shvatim had been assembled & given their "marching orders." Moshe was about to lead us triumphantly into the Promised Land.

But then, sadly, it all broke down. We degenerated into constant complaints & squabbles; Moshe lost his temper & castigated us severely. The episode of the Spies would seal our fate; we would wander 40 years in the desert before crossing into Israel, & then it would be without Moshe to lead us.

The "additional" book which Rebbi refers to is one that we could & should have written, but never did. The book describing our Aliya to Israel was left undone. It is therefore encased in a kind of parentheses formed by the 2 nuns.

But I suggest that the nun has another connotation: In the Ashrei prayer, it is the only letter missing. Chazal say it's omitted because it stands for "nafal" or fallen, a negative word. But every letter can represent some negative word! But maybe the link is to these nuns in our Sedra: Here, too, we failed, or fell, from our task (nafal=fell, fail).

Yet the glorious promise of this missing "Special Sefer," this final chapter in our glorious history, has only been delayed, not deleted. The day will come - is coming! - when Hashem will indeed scatter all of our enemies, & return all the tens of thousands of the House of Israel back to our rightful home in Israel.

And as for those nomadic nuns - they will then right themselves & proclaim a new & positive connotation: Nun for Nitzachon - total, eternal victory.