Type-safe collections, constraints, covariance — reusable code without boxing or runtime casts.
Five passes over the same idea, each from a different angle. Do them in order, or jump to whichever you need.
C# generics enable type-safe, reusable code. Key concepts: generic classes/methods/interfaces, constraints (where T : class, struct, new()), covariance (out T) and contravariance (in T), generic collections, and performance benefits over boxing/unboxing. Foundation for LINQ and modern .NET.
