- A serial is a story that continues in episodes, like a soap opera. Episodes usually aren’t full novel length, but that’s not really a hard and fast rule. The hallmark of a serial is a cliffhanger at the end of each episode to encourage you to purchase the next installment.
- A series is a collection of connected stories, each able to stand on its own. Some issues may be left unresolved until the whole series ends, but the main story thread in each book has a satisfying ending.
There may be several reasons why an author releases a story in installments. Some I can think or are: each episode is long enough to serve as its own novel (50,000 or more words); to build a loyal following of readers; to lure readers into paying more money for a story released in installments than they would for a single book. The first two reasons make sense to me; the third smacks of mercenary manipulation and seems underhanded.
Since I enjoy reading book reviews, I can tell that there are many readers who detest serials and will leave negative feedback and cliffhanger warnings. I don’t particularly like serials and will thank a reviewer for leaving a cliffhanger warning if the author doesn’t explicitly state in the book blurb that the book I’m considering purchasing is merely an installment in a serial. More often than not, I will decide not to purchase the book.
Back in the ’80s and ’90s, I bought series that, in all honesty, were serials: The Belgariad, the Mallorean, Thomas Covenant the Unbeliever, the Shannara series, etc. However, when I started them, I knew they were going to continue over multiple volumes. It was difficult–and can still be–to find a standalone fantasy novel. With the advent of indie publishing, there are more standalone novels than ever–and more serials.
So, what’s better? It’s purely a matter of preference. There’s no right or wrong. To other writers, however, I ask you to please, please, please specify clearly if your book is part of a series or a serial. That courtesy annoys far fewer readers than not doing so.