The guides routinely know how to navigate this no man's land and thankfully we got through with no problem.
The visa was no problem either. 30 Euros and it was stamped in my passport. The Mauritanians were happy to see us and we pushed through with a minimum of fuss.
Good thing too because in my pack was a prohibited item in the Islamic Republic of Mauritania: Jim Beam whiskey. Islam preaches that Jim Beam is evil and after some careful thought I agree, he must be killed. Preferably slowly with Coca Cola and lemon.
Note: Why you have to buy the book.
Mauritania yielded some of the richest stories yet including...
-Snak Shak Iraq, a restaurant ran by a former Iraqi P.O.W.
-Restaurant scams (a high art in Mauritania)