This chapter, Steady-state power, deals with computation of the steady-state power in AC circuits. Expressions for the energy dissipated by resistors and stored by capacitors and inductors are derived in both the time- and frequency-domains. Power factor is defined and the methods to improve it are described. The relation between the stored energy and the reactive power is clearly pointed out. A number of examples of AC circuit analysis are presented with clear explanation of all the steps involved from problem formulation to finding the solution. Supplementary programs for verifying the analytically obtained results by coding are available.