In a form of entertainment where the next installment might be a year or more away, can an author get away with a book-ending cliffie without angering her readers? Absolutely. Should she? Well, that depends.
Let's first differentiate between an actual cliffhanger and just an ongoing series with unresolved issues, plotlines, and story arcs at the conclusion of a book. The latter is what makes a series a series. According to tvtropes.org, an actual cliffhanger "ends an Act, Break, Episode, or even a whole season (for a TV) with some or all of the main characters in peril of some kind and the audience is made to wait for the outcome.
Karen Marie Moning did it in her Fever series. Each book ends with a cliffhanger that gets progressively worse for the heroine. However, the genre and point of view allowed for it. Readers of urban fantasy and paranormal are looking for a different story than a contemporary romance reader. They expect an ongoing series to be a long, complex story and aren't surprised by a cliffhanger ending that has them chomping at the bit for the next book. On the other hand, sometimes a contemporary romance reader won't take as kindly to a cliffhanger in an ongoing series. In Consensual by Livia Jamerlan I was put off by the end that leaves the heroine in a hospital bed just as nothing got resolved. It felt like a bait that I wasn't content with taking. Giving a little resolution with the peril may have made the break easier.
The payoff has to be enough to justify the anxiety a cliffhanger produces. Romance readers are expecting a happy ending. If a book ends with a cliffie, then the resolution should be worthy of their emotional investments. The worst cliffhanger payoff in history takes us back again to Dallas with its Bobby Returns cliffhanger, ending a season with Pam walking in on a supposedly deceased Bobby alive and well in the shower. Speculation ran rampant all summer long, and for those of you who remember, no doubt you're already groaning at the "it was all a dream" resolution — a perfect example of how to tick off your audience by not only giving them an inadequate payoff, but also discounting their previous investment of time and emotion.
Wise cliffhangers can inject added drama and excitement into a series and don't have to come at the end. A small cliffhanger at the end of a chapter keeps the pages turning into the night because they "have to find out what happens." Like a figurative roller coaster, mini-cliffhangers can give readers repeated emotional highs followed by payoffs that make them glad they picked up that novel.
The cliffhanger that I personally think should be avoided 99% of the time is the Ambiguous Ending cliffhanger. Gone With the Wind comes to mind, as does the film Inception. Readers want to know what happens to the characters they've become invested in, so an open ending that leaves ambiguity as to the burning question throughout the book may leave readers with a sour taste.
What about you? What do you think about cliffhangers? Love them? Hate them? Have a favorite? Tell me in the comments.