The Duke in Disguise by Gayle Callen

Who is this man?

The Duke of Thanet may have hired her as a governess to his six-year-old son, but there is something . . . different about the devilish rogue standing before her today. He seems to study her with an intensity she never noticed before, and he is certainly more charming than the last time they encountered each other. Was there always an alluring glint in his dark eyes? But the duke has a notoriously scandalous reputation, and Meriel will not let herself succumb.

Masquerading as the duke was not the simple solution Richard O'Neill had envisioned. When his ailing half-brother, the real duke, asked him to protect his young heir from a greedy enemy, Richard agreed. But he never thought he'd be attracted to the inquisitive governess, or that each moment in her intoxicating presence would tempt him beyond all reason. And letting down his guard could prove dangerous . . . especially to Richard's own heart.