Moore primarily produced and sold reprints of English and Scottish books.
Moore’s books were technically legal because British copyright protections did not apply in Ireland until after the Acts of Union 1800.
Moore advertised the edition as the largest and most expensive publication to date in Ireland.
[1] Like the Edinburgh third edition, Moore's Britannica was published in 18 volumes, containing more than 14,500 total pages and 542 copperplate engravings.
This leads to the curious situation where the pirated version of a work has an earlier date than the original.