At the beginning, the father's mathematical genius and the daughter's opinion of this are nicely summed up in this description:

However, I would not recommend that fans of mathematical fiction seek out this book (difficult to obtain, at least in the US) simply because the father is described as a mathematician. In fact, the rest of the book has practically no connection to mathematics. So, I will be giving this a relatively low rating for "mathematical content". (Again, this is not an insult to the author, only an acknowledgement of the fact that math plays only a very small role in the book.)

Still, I am adding this work to my database since it makes use of a common (and, in my opinion, unfair) stereotype of mathematicians. He is shown to be not only a cruel man, who ignored his daughter and cheated on his loving wife, not just an anti-social misfit who mistreats his house guests, but (as the title implies) practically insane.

Again, this has little to do with the rest of the book (aside from the fact that it lays the groundwork for the cruel task he sets for his daughter). However, it is for this exact reason that the author could have chosen to make him a cruel and crazy man in any profession. The book would not have been significantly different had he been the manager of an appliance store or a chemist (either in the American or British sense of that word). However, I fear, it has gotten to the point that authors automatically choose to make a character a mathematician when he is to be cold and evil, much as they used to make them Jewish when they were to be greedy.