James Blish 
Doctor Mirabilis [EPUB ebook] 
After Such Knowledge Book 2

This is the strange, compelling story of Roger Bacon. Ambitious, impatient, mutinous, Bacon was a man of his times with a vision reaching far beyond even our own day. Subject to the harsh, narrow confines of Church-dominated 'science’, Bacon dared to venture into the deep waters of theory, risking deadly accusations of heresy and black magic. Set against a vividly realised backdrop of thirteenth-century England, Paris and Rome, this is an engrossing account of this lonely prophet and suspected sorcerer.