This series proposes that life is not a biological special case but a thermodynamic inevitability — the stable trajectory of matter converging on self-perpetuating coherent energy processing wherever a sustained gradient, a constraining geometry, and feedback between energy routing and structural stability co-occur. Beginning with the alkaline hydrothermal vent as the first gradient-constrained system, the series traces an unbroken physical narrative from the spontaneous precipitation of iron-sulfur mineral clusters through the origin of replication, the formation of the first cell, the divergence of life’s domains, and the recursive encapsulation events that produced the eukaryotic cell and biological complexity at every subsequent scale. The central mechanism — encapsulation of an energetically active system by a boundary that forms around it through sustained intimate contact — appears at every major transition in the history of life, from the first fatty acid vesicle enclosing a fragment of mineral chemistry to the archaeal cell that grew around the bacterium that became the mitochondrion. Life evolves by enclosing energy systems that are too valuable to remain outside. Evolution is the history of successful enclosures.