Stairway to Forever

From the back cover of the Baen first edition: "In a strange new world he finds friendship, treasure... and danger. Life has not been easy for "Fitz" Fitzgilbert. He has survived the battlefield, personal tragedy, and economic hardship: now all he wants is peace. He moves into an isolated, ramshackle house built - oddly - on an earthen mound. The he uncovers a hidden stone passageway beneath the house - and falls through an invisible doorway into another world! Except for the bizarre beasts that crawl it shoreline, the "sand world" seems deserted. Yet Fitz is not alone. First he is visited by an old friend, who reveals that Fitz has a mission in this strange new world. The he is supplied with traveling companions: a Norman knight, transported from the 11th century via unexplained magic; and a 1950s jazz musician trapped in a most unusual new body. Together they will surmount incredible dangers - and reap incredible rewards!"