Every book evolves in its own way at its own pace, and sometimes it combines with other books or divides like an amoeba into two.  Progeny’s Child and The Brazen Anvil began as one idea but became primary and sequel later, as one idea sparked another. The process is organic, usually acting through the characters. I had to learn to let them write the dialog and even the plot. If they did not want to say or do what I said, they made the process tedious. This was particularly true of romance. In The Earthborn Men, I intended that Jason and Atalanta be lovers, but the minute I left Jason and Sanchez alone together, they jumped each other. Besides, Atalanta was clearly very fond of Brother Mikal, despite his vows.