Mary-Jo Wormell, its thrice-married founder and a former Conservative Party parliamentary candidate, spent 20 years as a Mills & Boon author, writing more than 40 titles under the nom de plume Mary Lyons. Mary-Jo along with two other prolific Mills & Boon authors launched Heartline Publishing on 14th February 2001. The publishing house was meant to fill the gap between Mills & Boon and Mainstream fiction.