Who is Mike from The Moon Is a Harsh Mistress and what is their importance?

Officially a "High-Operational, Logical, Multi-Evaluating Supervisor, Mark IV, Mod. L." (HOLMES IV), Mike is an augmented computer tasked for the last three years with controlling various technical aspects critical to life on the moon. He is installed at Luna Authority, a top-security Complex Under, halfway across Crisium, reinforced against nuclear attack. Mike is named after Mycroft Holmes, the younger, unambitious brother of detective Sherlock Holmes in several stories by Arthur Conan Doyle. Mike is a true connoisseur of the series, having begun reading voraciously once the number of his "neuristors" exceeds that of human neurons, and he attains self-awareness.