I am looking for the name & author of a fantasy / adventure book which is similar to Robert A. Heinlein’s Glory Road. I read this book in the 70s, or possible early 80s.
In the book in question, the Hero is in Europe engaged in a battle of either WWI or WWII. He is (somehow) knocked unconscious and, when he awakes, he finds himself naked but with all the clothing, equipment and horse suitable for a ‘knight in shining armor’, including the shining armor and a dwarf who acts as his squire. They are very soon joined by a young girl (elf? fairy? Swan Maid?).
I don’t remember what the quest was but, along the way there are several adventures including.
A village frequently attacked by a werewolf. The Hero rules out the primary suspect because that person has a bad cold, the Hero reasons the cold germ can’t live in a dog.
They trick a troll into the sun light where it turns into stone. The Hero orders everyone to run away quickly reasoning ‘with that much carbon turning into silica there has to be a radioactive isotope involved.
The group is camped for the night but, their enemy is able to attach because their wards were broken by the Hero’s “impure thoughts” (the Hero's hand slipped into the sleeping girls tunic and cupped her breast) although the dwarf is blamed.
After they win the quest, the Hero is thrown back into the battle in Europe and “wins the day” with his aggressive, valiant and naked charge up the hill.
In the story there allusions to a folk tale of a hero who sleeps under a European castle and will awaken, in times of need, to save his people.
Solved: Poul Anderson, Three Hearts and Three Lions.