Centered on the conspiracy in 1478 to kill the Medici brothers Guiliano and Lorenzo, and to take control of Florence, Martines provides a fascinating look into the politics of Renaissance Italy.  In the 15th century, Italy was a chaotic blend of princely states, Papal feudal states, city- states and republics, surrounded by opponent in France, Germany and Turkey who cleverly played all sides against each other.  The Catholic church's involvement was at its height, and a successful business family needed to maintain extensive trade alliances around the Mediterranean, along with  political  and clerical alliances, strengthened by marital arrangements and appointments in the Church.

Well written, Martines does an excellent job of describing all these facets, while still maintaining a storyline as intriguing as anything Dorothy Dunnett wrote (Readers of her Niccolo series will in fact, recognize many of the characters, quarrels and subplots from her books.) The financial chapters are especially interesting, since they describe a pre-capitalist economic system  that worked quit differently from our modern one. Banks, for example, were much more the tools of private families, and nations didn't exist, but were instead led by princes and kings [See Shield of Achilles] who usually lacked a secure fiscal backing, and so were dependent on ever shifting alliances and loans from individual families.  The complicated nature of this system is described by Martines:

"In relations with Milan, Lorenzo was the client always, and Galeazzo Maria Sforza the patron, 3even though that princely house was nearly always the debtor of the Medici Bank.  On his death in 1466, Francisco Sforza owed the Medici 115,000 ducats, security for which lay in pawned jewels and in assigned salt taxes, and over the next year or two ... would rise to the fantastic sum of 179,000 ducats.  The dukes, however, lords of one of Italy's greatest states, had the soldiers to defend the Medici if the need arose, always provided that the Medici maintained enough control in Florence to command the city gates. And neither the first nor the second of these points was ever forgotten."