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+# Callisto
+
+A featureful runtime for Lua 5.4, written in C99 using POSIX APIs.
+
+Callisto is an extension to Lua that adds commonly-needed functions
+and features to the language, and includes a file library to manage
+and manipulate files, a process library to find active processes and
+manipulate signals, a socket and networking library using LuaSocket,
+and a JSON manipulation library *among many more*.
+
+Before I made Callisto, I usually had to rely on three libraries:
+luaposix for basic file manipulation and other routines, lua-cjson
+for JSON parsing support and LuaSocket for networking.
+
+First and foremost, Callisto tries to satisfy these requirements:
+ - an all-in-one zero-dependencies library for Lua that includes
+   most features people would need, out of the box
+ - a library that works and integrates well with Lua and its
+   standard library, and is easy to use
+
+Currently Callisto only works on POSIX operating systems such as
+Linux and the BSDs (mainly because I don't have a machine running
+Windows).
+
+## Dependencies
+
+To build Callisto, you'll need a C compiler and *ar* (a standard
+Unix archiving utility, should be included on every major Unix).
+The default C compiler is *cc* which is usually a symbolic link to
+your system's default C compiler. This should be gcc on Linux, and
+clang on most of the BSDs. If *cc* doesn't exist on your system,
+change the `CC` variable in the Makefile to your desired C compiler.
+
+At runtime you will need the following libraries:
+ - libdl: for loading C modules
+ - libm: basic math operations
+ - libreadline: REPL history
+ - (Linux only) libbsd: Utility functions from BSD operating systems
+
+All of these are very common and should be already installed on
+your machine.
+
+## Installation
+
+Callisto is distributed as source-only, but don't worry, it's
+not hard to compile.
+
+First, get the source code using `git clone https://github.com/jtbx/callisto`
+then in the newly created directory, run `make` to compile Callisto.
+The compiled executable will be named `csto`, and does not depend
+on any Lua .so C modules or Lua files.
+
+To install `csto` (the Callisto standalone executable) and
+`libcallisto.so` (the Callisto shared library), run `make install`
+as the root user in the source code directory.