Mass. Gen. Laws ch. 183 § 4
A conveyance of an estate in fee simple, fee tail or for life, or a lease for more than seven years from the making thereof, or an assignment of rents or profits from an estate or lease, shall not be valid as against any person, except the grantor or lessor, his heirs and devisees and persons having actual notice of it, unless it, or an office copy as provided in section thirteen of chapter thirty-six, or, with respect to such a lease or an assignment of rents or profits, a notice of lease or a notice of assignment of rents or profits, as hereinafter defined, is recorded in the registry of deeds for the county or district in which the land to which it relates lies. A "notice of lease", as used in this section, shall mean an instrument in writing executed by all persons who are parties to the lease of which notice is given and shall contain the following information with reference to such lease: the date of execution thereof and a description, in the form contained in such lease, of the premises demised, and the term of such lease, with the date of commencement of such term and all rights of extension or renewal. A "notice of assignment of rents or profits", as used in this section, shall mean an instrument in writing executed by the assignor and containing the following information: a description of the premises, the rent or profits of which have been assigned, adequate to identify the premises, the name of assignee, and the rents and profits which have been assigned. A provision in a recorded mortgage assigning or conditionally assigning rents or profits or obligating the mortgagor to assign or conditionally assign existing or future rents or profits shall constitute a "notice of assignment of rents or profits".
Mass. Gen. Laws ch. 183, § 4