Automake is a tool provided by GNU for the purpose of automating the generation of portable, configurable Makefiles.
Automake is a tool for automatically generating Makefile.ins from files called Makefile.am. Each Makefile.am is basically a series of make variable definitions, with rules being thrown in occasionally. The generated Makefile.ins are compliant with the GNU Makefile standards.
The GNU Makefile Standards Document (see Makefile Conventions) is long, complicated, and subject to change. The goal of Automake is to remove the burden of Makefile maintenance from the back of the individual GNU maintainer (and put it on the back of the Automake maintainers).
The typical Automake input file is simply a series of variable definitions. Each such file is processed to create a Makefile.in. There should generally be one Makefile.am per directory of a project.
Automake does constrain a project in certain ways; for instance, it assumes that the project uses Autoconf (see Introduction), and enforces certain restrictions on the configure.ac contents.
For more details, take a look into automake manual
