Barron, Stephanie. Jane Austen mystery.

"November, 1815. The Battle of Waterloo has come and gone, leaving the British economy in shreds; Henry Austen, high-flying banker extraordinaire, is about to declare bankruptcy dragging several of his brothers down with him. The crisis destroys Henry's health, and Jane flies to his London bedside, believing him to be dying. While she's there, the Reverend James Stanier Clarke, chaplain to His Royal Highness the Prince Regent, invites Jane to tour Carlton House, the Prince's fabulous London home. Clarke is a fan of Jane's books, and during the tour he suggests she dedicate her next novel Emma to HRH, whom she despises. However, before she can speak to HRH, Jane stumbles upon a body sprawled on the carpet in (where else?) the Regent's library. The dying man, Colonel MacFarland, was a cavalry hero and a friend of Wellington's. He utters a single failing phrase: "Waterloo map" and Jane is on the hunt for a treasure of incalculable value and a killer of considerable cunning"--