Book 1, a fantasy, overall was a good book. The story was quite clever, and I had a hard time putting it down. Until...it occurred to me, a couple times after the 3/4 point that this novel was going to continue in another book. Perhaps I should have assumed "series" since this is a fantasy novel; however, it bothered me the writer was setting me up for a second book when I wasn't finished with Book 1 yet. The ending was okay, and would have been so much better if plot threads were tied up.
Book 2, a historical fiction novel, had such a satisfying ending, it took me by surprise there would be a continuation of the story. Don't get me wrong. I'm looking forward to finding out what happens to the characters in the next book--I already have an idea of the story that needs to be told next; however, the author did such a beautiful job with plot and character arc, the novel was fine--as is. The story...the ending was perfect. Not a happily-ever-after ending. Not a dismal ending. Simply a courageous, realistic ending that worked so well for this time period.
This all makes me wonder, what do you think makes a satisfactory book ending--in a stand-alone book? in a book series? I'd love to hear your thoughts.