Answer
The librettist for "Lucia di Lammermoor" was Salvatore Cammarano, a renowned Italian opera librettist of the 19th century. He is particularly celebrated for his collaboration with the prominent composer Gaetano Donizetti, and their partnership produced several iconic operas, including "Lucia di Lammermoor," which premiered in 1835 and remains a cornerstone of the bel canto repertoire.