The C Standard Library is a collection of pre-written functions and macros that provide essential tools for C programming. It includes functionalities for input/output operations, string manipulation, memory management, and mathematical computations, among others. This library helps programmers avoid rewriting common code, promoting efficiency and consistency in software development. The library is standardized by the ISO (International Organization for Standardization), ensuring that C programs can be compiled and run across different platforms without modification. Key components of the C Standard Library include headers like stdio.h for input/output, stdlib.h for general utilities, and string.h for string handling.