Readme includes basic project idea and motivation.

README.md

@@ -1,2 +1,29 @@
 # minetest-cereal
-What can I find out about the Minetest World database format?
+
+What can I find out about the [Minetest](http://www.minetest.net/) world
+database format?
+
+The [How to Code - Systematic Program
+Design](https://www.edx.org/xseries/how-code-systematic-program-design)
+course has shown me that if you design your data well, it's easy to
+write good clean code.  "Good" meaning code that is well structured, and
+easy to understand.  Even better, well designed data can guide you to be
+more effective at actually writing complicated algorithms.
+
+When I got curious about how Minetest represents worlds, I was
+pretty excited to discover that they use a SQLite database to store the
+map.  I'm comfortable with SQL, and expected to be able to
+jump in and start reshaping imaginary planets.
+
+No such luck!  Turns out their data structure was put together
+more or less by accident.  It consists of a single mathematically
+derived number to represent the X,Y,Z coordinates of a given block, and
+a binary blob that serializes whatever information there is to know
+about that block.  Neither of the representations are readily
+comprehensible by humans.
+
+This project will attempt to decode databases in the existing Minetest
+format into one that fits the standards of the Systematic Program Design
+course.  I want to make it easier to alter and explore Minetest
+world maps as data, and to convince you that data should be designed so
+that people can understand it too.