Flori (1579-1647) was an Italian Jesuit who lived mostly in Sicily (which explains the printing place of this work) for the administration of the Jesuit Province; Peragallo, in a lengthy note, explains:

“It is an outstanding work. Flori’s precise and clear-cut definitions and his illustrations of double-entry books testify to his firm grasp of the subject of bookkeeping. He was well acquainted with the writings of previous authors, whom he divides into two groups: writers of mercantile bookkeeping, such as Paciolo, Casanova, Manzoni, Tagliente, Moschetti, Grisogono, and others; and writers of administrative bookkeeping (libri nobili), such as Simon Stevin and Don Angelo Pietra… In his introduction, Flori says that, although several systems of bookkeeping have been developed by the ancients, only double entry, which had its origin in mercantile transactions and trade, reached perfection. He tells how gradually it came into use by enterprises of a non-mercantile nature, such as hospitals, religious orders, government, and family economy. It is evident that Flori was fully aware of the advancement made in bookkeeping. His contribution was responsible for a large share of it. With Pietra and Flori, the literature of bookkeeping takes cognizance of the expansion of double entry beyond the orbit of the mercantile firm and the emergence of the entity of the enterprise as distinctly separated from its one or more owners” (Peragallo, pp. 83–88).

Flori’s work aimed to “easily trace the course of transactions through the accounts and also learn how income and expenses are properly allocated to the fiscal periods in which they arose… the first time that an author mentions the placing of transactions in their proper fiscal periods” (Peragallo). It is also the first mention of a suspense account, the first to distinguish between the trial balance, ledger closing, and financial statements.

The book was published again in an also rare (not as rare though) Rome edition in 1677.

Peragallo, Origin and evolution of double entry bookkeeping: a study of Italian practice from the fourteenth century (1938); Sommervogel III, 804–5.1; not in Einaudi.