The Book of XEN A Practical Guide for the System Administrator

Once upon a time, in the land of Armonkwhere-the-shadows-lie, a band of fiendish programmers were weaving their evil schemes. And it seemed that dark days were upon the earth at last, and for all time, for the programmers seemed so very clever that no one would ever be able to stand against them. And even if some hero were, through great fortune
or unimaginable heroism, to bring one low, then there would still be an innumerable quantity remaining, each more fiendish and subtle than the last.