Asked by the TLS to name his book of the year, William Boyd plumps for James Hanning’s life of the super-spy Kim Philby. He remarks:

‘What continues to intrigue about Philby after all these decades is his astonishing ability to maintain his double-life with such devious aplomb for so long. It showed a true, virtuoso dedication to the the art of duplicity, if such a thing exists.’

I think it does. There’s no joy in it, and we all have it in us to practise it, even if not to the level of virtuosity. Hence the abiding force of the Biblical injunction to cultivate an undivided heart.