Silhouette was originally the Silhouette Book Publishing Division of Simon and Schuster, specializing in category-length romance. The Silhouette imprint was acquired by Torstar, the parent company of Harlequin Enterprises Limited in 1984. Since that acquisition, the competitive nature of the category market has declined. Harlequin retains the Silhouette name and continues to publish popular lines under the Silhouette imprint.
Since the renaming of Silhouette Nocturne and Silhouette Nocturne Bites to Harlequin Nocturne and Harlequin Nocturne Bites in 2008, and 2010 respectively, all remaining Silhouette imprints from April 2011 became Harlequin imprints.
- Silhouette Desire
- Silhouette Intimate Moments - renamed to Silhouette Romantic Suspense in 2007
- Silhouette Nocturne - a paranormal imprint launched in 2006
- Silhouette Special Edition
- First Love - The First Love imprint changed to Silhouette Crosswinds.
- Silhouette Bombshell - the line was discontinued in 2007
- Silhouette Crosswinds - The Silhouette Crosswinds imprint was geared toward the Young Adult romance market.
- Silhouette Nocturne Bites - a paranormal short e-book imprint launched in 2008 under Silhouette imprint and last book was published December 2011 under Harlequin imprint.
- Silhouette Romance - merged with the Harlequin Romance imprint in 2007
- Silhouette Shadows - romances from the Dark Side of Love, ran from 1993 to 1996
- Yours Truly - a romantic comedy line, which merged with the Harlequin Love And Laughter line in 1999 to form Duets.
- at the Harlequin page
- 36 Hours
- American Heroes
- Dakota Fortunes
- Daughters Of Myth
- Debbie Macomber's Navy Series
- Dynasties: The Elliotts
- Forbidden Fantasies
- Hotel Marchand
- Mediterranean Nights
- Singles...With Kids
- Texas Hold 'Em
- The Best of Betty Neels
- The Boss's Mistress
- The Brides of Bella Lucia
- The Fortunes of Texas: Reunion
- The Secrets of Stoneley
- Those Sexy O'Sullivans
- Wingmen Warriors