A state selected at random from the Hilbert space of a many-body system is overwhelmingly likely to exhibit highly non-classical correlations. For these typical states, half of the environment must be measured by an observer to determine the state of a given subsystem. The objectivity of classical reality--the fact that multiple observers can each agree on the state of a subsystem after measuring just a small fraction of its environment--implies that the correlations found in nature between macroscopic systems and their environments are very exceptional. This is understood through the redundant recording of information about the preferred states of a decohering system by its environment, a phenomenon known as quantum Darwinism. To see this in action in the real world, we first consider the ubiquitous case of blackbody illumination. We show that it exhibits fast and extensive proliferation of information about an object into the environment, yielding redundancies orders of magnitude larger than the exactly soluble models considered previously. Turning to a universe of qubits, we examine the conditions needed for the creation of branching states and study their demise through many-body interactions. We show that even constrained dynamics can suppress redundancies to the values typical of random states on relaxation timescales, and prove that these results hold exactly in the thermodynamic limit. Finally, we connect these ideas to the consistent histories framework. Building on the criterion of partial-trace consistency, we introduce a sensible notion of mutual information between a fragment of the universe and a history itself. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]