Ever had this experience of reading a book in which there is a bookmark some twenty pages in & the corner of page 205 turned down & noticing that certain lines at various intervals have been discreetly marked with a small dot implying some kind of importance & knowing that it was you who inserted the bookmark & turned down the page & marked those lines for future reference & yet, for the life of you, cannot remember either having done so or the vaguest recollection of why or even - worse still - the dimmest recollection of the narrative ...?

Senility beckons.