There are guides, good guides - and then there is Malcolm Miller, English guide to Chartres Cathedral for more than fifty years.
In October 1986 I spent a few days in Paris and took the short train ride out to Chartres to see the cathedral. Noticing a sign advertising 'Tours in English', I tagged along - and fell under the spell of MM.
Softly spoken, deliciously theatrical, MM draws you in with his whispered opening line: 'I'll tell you a secret...'
And you're away, the cathedral's long life unfolding while Miller shows you how to 'read' its 'hidden meaning' - particularly through its miraculously complete, totally integrated programme of stained glass and statuary.
Hint - for the best possible time, take your binocs.
And by 'hidden meaning', he doesn't mean 'da Vinci-style' esoterics - he's referring to the fact that the whole place tells a single narrative - which I guess could be summed up as the story of salvation.
History, engineering, gossip, theology and, well, a kind of numinous glory - these are all elements of the MM experience - all the more intense if you have a prior inkling of the broad sweep of the Bible - from the garden to the heavenly Jerusalem.
I was so mesmerised on that long-ago Tuesday that I joined his afternoon tour as well - and returned for two more on the Thursday.
Two 'MM neophytes' accompanied me when I returned to the Cathedral recently - after a gap of twenty-two years. I worried that the 'magic' might have faded and that they would feel let down after my enthusiastic trumpeting of Mr Miller.
My fears were groundless.
His hair is whiter, his posture a liitle stooped, but his style, erudition and élan remain undiminished.
Catch him while you can.
And here, from a 1980s documentary film, is a glimpse of MM's enthusiastic approach: