This document contains chapters from the textbook "Introductory Circuit Analysis" by Boylestad on network theorems. It discusses the objectives of learning superposition theorem, Thevenin's theorem, and Norton's theorem. The chapter on superposition theorem explains that it allows analyzing circuits with multiple sources by considering each source independently and summing their effects. It provides examples of applying superposition theorem to determine currents and voltages in circuits. The chapter also discusses Thevenin's theorem, which allows reducing any two-terminal network to a single voltage source in series with a resistor.