This invited lecture concerns Plasma-Focus (PF) devices belonging to the family of the dynamic Z-pinches which produce dense, hot and magnetized plasmas. The plasma is formed by an inter-electrode discharge of a capacitor bank, and the dynamics of the current sheet has two different phases: 1—A long-time phase (lasting several microseconds) of a breakdown and the axial acceleration, during which the current sheath is formed and pushed out by the Lorentz force; 2—A short-time phase, lasting a few hundreds nanoseconds, during which the pinch is created and (after the maximum compression) disrupted by instabilities. This lecture presents physics governing the behavior of current-carrying plasma in PF discharges. The lecture describes different phases of the PF phenomena: the breakdown and the early stage of the current sheath formation, dynamics of the axial acceleration (run-down) and the radial implosion, the formation of a transient quasi-equilibrium near the stagnation point, and a post-pinch phase. Some experimental results obtained with a large (mega-joule) PF-1000 facility are presented and discussed.