No predetermined number of books. Usually author-driven (Catherine Mann’s Wingmen Warriors, Alexandra Sellers’ Sons of the Desert), but can also be an ongoing miniseries with multiple authors in a line like The Wrong Bed in Temptation, which moved to Blaze in 2005.
Pros: Individual author’s ongoing series allows creative freedom to add characters to an extended community familiar to readers. A line miniseries like The Wrong Bed allows authors to contribute to an already popular product with built-in readership.
Possible Cons: If an author wishes to walk away from an ongoing series for contractual reasons, there may be remaining characters that she cannot take with her.
Developed in house by the editorial staff or freelance writers, continuities are long (a year or more) miniseries with multiple authors contributing. Can be in line or out of line. Examples: Code Red, Montana Mavericks, Athena Force, Family Secrets, Dynasties: The Ashtons.
Pros: Allows authors to participate in a well-advertised product with other authors who each bring their individual readerships to the larger series. Necessitates working with other authors, which can lead to useful and fun networking.
Possible Cons: Your assigned storyline might not resonate with you personally. Occasionally, working with other authors can lead to thwarted creativity when participants don’t share your vision.
Finite number of books planned out in advance. Trilogies are popular, but other formats are possible. Can be cross-line (Joanne Rock’s Single in South Beach) or in-line (Jennifer Greene’s Scent of Lavender).
Pros: Creative freedom!
Possible Cons: You’ve only got your name to rely on.
Finite number of books in a series with multiple authors contributing. This kind of miniseries is plotted and pitched by the authors. Examples: Lock n Key in Blaze.
Pros: Other authors bring new readership to your work. More creative brainstorming power.
Possible Cons: Must play nice and work for the greater good.