Michael of Rhodes was a Venetian mariner whose career spanned the first half of the fifteenth century. He compiled a book of useful information for sailors, including tables for keeping track of times and dates, navigation methods, mathematical calculations, and information on the construction of ships.
The sole manuscript of his book has belonged to private owners and remained unavailable for study until a new owner allowed a team of scholars to have access to it in 2000. They have now produced a two-volume edition and translation of the work, plus an additional volume of interpretation.
Medievalists.net has more information and an interview with the team of scholars.