Md. Code, Education § 23–108

(a) Subject to the provisions of subsection (b) of this section, a public, school, college, or university library in this State shall prohibit inspection, use, or disclosure of any circulation record or other item, collection, or grouping of information about an individual that:

(1) Is maintained by a library;

(2) Contains an individual’s name or the identifying number, symbol, or other identifying particular assigned to the individual; and

(3) Identifies the use a patron makes of that library’s materials, services, or facilities.

(b) A public, school, college, or university library in the State shall permit inspection, use, or disclosure of the circulation record of an individual only:

(1) If necessary for the reasonable operation of the library;

(2) On written consent of the individual; or

(3) By subpoena or court order.