Thanks, Jellby... I DID try using "clear:both" pretty much exactly as you suggested, but the deeper problem is the lack of comformity between 90% of Readers or Reader apps, all using the ePub file format that DOES recognise the "float" command, and Amazon's Kindle, which uses the MOBI format that does NOT recognise "float", but still has a strangle-hold on 90% of the eBook market. It's a dilemma. You don't want to write 2 versions of every page that needs illustrations... that just gets too hard to manage.
In the end I just edited the illustrations to make rows of images (similar to those shown in my signature) no more than about 300 pixels wide – about a half an average "page", then placed the synopses below that. It looks ok in either format, which is the main thing.
Short synopses of 4 novels
Short synopses of a trilogy
Short synopses of a duology