Do you know where you put the window cleaner’s bill? Do you remember that you missed your last appointment at the dentist’s because you had mislaid her appointment card? When these things happen, do you put it down to just another senior moment or, perhaps, an indication of a worrying frequency of lapses in concentration, usually noted in older friends and relations? Might I suggest that you take a few moments to riffle through the last half-dozen books that you have read recently? You may be surprised at what you find.