The search for the structure of our Universe and our position within it never will cease. As we answer each question, others arise with even greater insistence. And the context of our questions is ever changing. From the mythological background of Babylon, to the mechanical clockwork of Newton, through the opening of our minds to prodigous swarms of distant galaxies, to the mathematical models of general relativity and gravitational clustering within them, each new context inspires new questions. Nor is there reason to suppose that the present context will bring this search to a close.

Throughout the roughhewn matrix of our understanding, dark matter weaves threads of uncertainty. Its amount governs the flight of the galaxies and the fate of the Universe. Many models undertake to confine it to various distributions and forms. So far, dark matter has resisted all but gravitational attempts at detection, leaving the models to flicker and shift in the ebb and flow of theoretical fashion.

Nor do observations always provide simple truths. Most are so riddled with selection and filtered with theory that their interpretation is seldom straightforward. Simple ideas like filaments and voids, walls and clusters, become much more complex when closely examined. Their simple grammar often remains suitable mainly for slogans. All good observers know this in their bones. Results, regardless, can still be astounding.