Book Four in the "Life and Travels of Da Vinci" series - though they can be read and enjoyed in any order Join Leonardo da Vinci as he returns to Florence, works on several painting commissions, and then joins the ruthless Cesare Borgia as his military advisor. This family-friendly historical novel covers about two and a half years of Leonardo's life - and his interactions with a number of contemporary luminaries: including Luca Pacioli (mathematician), Donato Bramante (architect), (Niccoli Machiavelli (Florentine ambassador and writer) and Cesare Borgia. Much of Leonardo's time with Borgia was spent travelling through the countryside of Romagna (central Italy) - examining fortifications and making military recommendations. This novel takes a look at the other things he was doing at the same time - sketching bell towers, examining interesting windows, sketching pigeon houses, and much more