Nine Rules to Break When Romancing a Rake (Love By Numbers)

is the first book in the Love By Numbers trilogy by Sarah MacLean.
==Book Description==
A lady does not smoke cheroot.
She does not ride astride.
She does not fence or attend duels.
She does not fire a pistol, and she never gambles at a gentlemen’s club.
Lady Calpurnia Hartwell has always followed the rules, rules that have left her unmarried—and more than a little unsatisfied. And so she’s vowed to break the rules and live the life of pleasure she’s been missing. 
But to dance every dance, to steal a midnight kiss—to do those things, Callie will need a willing partner. Someone who knows everything about rule-breaking. Someone like Gabriel St. John, the Marquess of Ralston—charming and devastatingly handsome, his wicked reputation matched only by his sinful smile.
If she’s not careful, she’ll break the most important rule of all—the one that says that pleasure-seekers should never fall hopelessly, desperately in love . 
(Description from MacLeanSpace.com)