Dissecting the Active Directory Infrastructure Master Role
Dean Wells has a very interesting and in-depth look at this FSMO role. This will actually be an 8 part series that looks into this DC role. Teaching AD for years this was always a mystery to students on what this role really did. For those that love the nitty gritty details this is what you have been looking for all along.
Article 1, Article 2, Article 3, Article 4, Article 5, Article 6