A Makefile is a text file used by the 'make' utility (and similar build automation tools) to control the compilation and building of software projects. It contains a set of rules that define dependencies between source files and the commands required to transform those source files into executable programs or libraries. Each rule typically consists of a target (the file to be built), a list of prerequisites (dependencies), and the recipe (shell commands) needed to create the target if any prerequisite is newer than the target itself. Makefiles are crucial in C/C++ development and many other compiled languages for managing complex build processes, ensuring that only necessary recompilations occur, which saves significant time during development cycles. They allow developers to define custom build steps, clean up generated files, and automate deployment procedures. The syntax is highly specific, relying on tabs (not spaces) to indent recipe lines, which is a common source of errors for newcomers to the tool.