Where did you get the idea for your most recent book?
It emerged, as with all the others, from a short story that I had written. That came from the 'ether'. Just emerged. It was one of the series of stories on infidelity that I talk of in one of my other answers. I sort-of got the first scene playing in my head, started writing it down, and it mushroomed, but in slow motion.
I don't 'get' the idea. It's more like the idea 'gets' me. Sometimes it's just a sentence; sometimes, as I've said above, a scene. I start writing the dialogue, or describing the scene, and it grows like Topsy...
In The Golden Pool I started off with the scene of a very happy man speeding down a highway towards his home, where catastrophe awaits. Much later one of my alpha-readers (who doesn't even know who I am...) suggested that it was the wrong scene with which to open the book. I was initially resistant. She suggested that I start with The Holiday Cruise. I didn't think that was a good idea, but did her the courtesy of copy/pasting it at the top and then re-reading it. This made me see what she meant, but it was still not quite right. Then one day I found myself writing the Fantasy-style opening, which then morphed into the slightly screwy stop/start scene-shifting opening. I loved this, and, fortunately, so did she.