A bifurcation represents a qualitative change in the solution of a differential equation or a system of equations that depends on parameters. It occurs when a small, smooth change in a parameter value causes a qualitative change in the behavior of the solution. It’s worth noting that the approach described in this chapter, while heavily involving the solution of the linear equation, ultimately yields an asymptotically exact solution of the nonlinear equation. This chapter presents a thorough collection of established mathematical principles related to soft bifurcations in nonlinear differential equations. Central to the text, the theory of soft bifurcations is foundational, enabling this chapter to function as a comprehensive reference and eliminating the need for supplementary textbooks.