What is it?

A good, NON-TECHNICAL place to start... 
Here's an easy-to-understand, non-techie "what, why & How" overview for those curious about MDM. Read full article.

Normalization.

Technical info...
Here's an interesting post that walks you through how to organize data in a relational database through Normalization. Details 1st, 2nd and 3rd Normal Forms. Visit page.