Researching Massachusetts legislative history and intent is a complicated process, but it has gotten easier in recent years using online resources. The State Library is still the most complete resource for legislative research, but it now also provides online information including a video about the legislative history research process, a legislative glossary and a comprehensive guide to researching the history of legislation.
The General Court has also put historical resources online. Senate and House Journals going back at least 10 years are now available. How an Idea Becomes a Law is a simple outline of the basic steps on the way to enactment presented in 13 colorful slides. You can even watch the archived Formal Sessions of the House and Senate on Legislative Broadcast Services to get a sense of what the members were thinking about pending legislation.
So while this type of research is still exacting and may in the end require a trip to the State Library in Boston, it is now possible to get much more research done before your journey and to be better prepared to take maximum advantage of the State Library's unique resources. The Trial Court Law Library locations throughout the state are great places for getting started on researching the history of a law.