This little book first appeared on the public stage to a small audience in 2011. The 2019 6th edition now bows out for the last time. There had to be further editions after the first when the author, his most severe critic, introduced new ideas and corrected the errors of the previous ones. But running through them all has been the strong thread of his conviction that the placental supply for the foetus feeds the left atrium, not the right, and that...