"Hast seen the White Whale?"

Why does my mind go blank when anyone asks what I'm reading?  I suppose another question might be what does it do when it's not blank?

I've just managed to get through Moby Dick by Herman Melville [1851];  a triumph of sorts, even if it did take me about five months during which I veered off to read lots of other books.  Without the many and lengthy asides, philosophical and scientific, the story of the hunt for the white whale would have been a novella, I'm sure.  Melville would have been aware that most of his readers would never have seen a whale, perhaps not even a picture, so he spends detailed chapters describing the physical attributes of Ahab's prey to the minutest degree.  There's one chapter about the jaw structure of the sperm whale.

( where I go on for more nonspoilery detail about the book )