Pulling together yet other worlds she felt had been artificially separated, Rukeyser wrote the biography of the mathematical physicist, Willard Gibbs. Gibbs, in the 19th century, devised visualizing methods which redefined the meaning of space. Instead of being a static Cartesian grid, his phase space could represent every possible lifeline of a system, any system, any number of coexisting systems. Gibbs's method, criticized by some as merely visualizing, was grasped at once by James Clerk Maxwell - the man whose equations define electronic reality - as both profound and productive. The very shapes of graphs and models yielded truths about energetics of the system - the relation of transitions to degrees of freedom and free energy; phase transition itself, as from ice to water, being a change of identity toward which the whole system was attracted.