It's called "The Silver Skull" by Mark Chadbourn. This book, set in Elizabethan England, has the following:
-secret agents (including Christopher Marlowe)
-sinister Spanish Agents with a twisted code of honor
-malevolent Faerie lords
-A doomsday weapon recovered in the New World by Sir Francis Drake
-An organization of occult investigators led by Sir Francis Walsingham (including Christopher Marlowe)
-The most famous spy in England (that's just his cover)
-Knights Templar conspiracies
-deathtraps, intrigue and swordplay
-A masquerade ball attended by the worst criminals in London
-A dog whose eyes glow in the dark
-A masked prisoner kept under special guard in the Tower of London
-A LOT of stagecoach chases
-animated living scarecrows
And so far, I'm only halfway through the book!
If you have any interest at all in the 7th Sea RPG, this is a must read, not only for Avalon (English) characters, but excellent inspiration for the secret society Die Kreuzritter as well.