The Art of Tying the Cravat: Demonstrated in Sixteen Lessons (1828).
Apparently, the ideal cravat style for a man with health issues, the Gastronome gives a casual air of elegance while being practical.
For more on cravats:
Regency Fashion: Putting on a Cravat – Regency Reader (regrom.com)
Regency Fashion: The Cravat a l’Americaine – Regency Reader (regrom.com)
Regency Fashion: Cravate a la Byron – Regency Reader (regrom.com)
Regency Fashion: Cravate Sentimentale – Regency Reader (regrom.com)
Regency Fashion: The Cravate en Cascade – Regency Reader (regrom.com)
Regency Fashions: Cravate Mathematique – Regency Reader (regrom.com)
Regency Fashion: Cravate a la Maratte – Regency Reader (regrom.com)