The Massachusetts Public Records Law (Law), found at Chapter 66, Section 10 of the Massachusetts General Laws, applies to records made or received by a Massachusetts governmental entity. Unless the requested records fall under an exemption to the Law, the responsive documents must be made available to the requester. A list of exemptions may be found at Chapter 4, Section 7(26) of the Massachusetts General Laws.
More information may be found here: http://www.sec.state.ma.us/pre/prereq/reqidx.htm