Phyllida Law has a delightfully natural style, a gift for anecdote and the knack of seeing the funny side of pretty much everything.  She’s a good actor: she’s obviously a fine cook, too, if the recipes in How Many Camels Are There in Holland? Dementia, Ma and Me (Fourth Estate, £12.99) are anything to go by. Also included are a series of her lovely watercolour sketches, of Tuscan villas, Christmas stockings, her mother asleep. Is there nothing the woman can’t do?

Someone so accomplished could write a book about their weekly trip to the supermarket and make it highly amusing. A volume about her mother’s decline into dementia is hardly a more promising proposition, yet this is a funny, brave and heartening volume.

Concealed within its whimsy is much sadness and also an important truth: that the people we love can still be very fully themselves, even when memory and recognition and language fail. Law’s mother is slightly monstrous, secretive, sometimes commanding, often exasperating. She is also plucky, resourceful, hilarious and full of brio. In other words, Alzheimer’s can’t knock the character out of her.

As more and more of us encounter this ghastly affliction, we need guide books. If Oliver James’s excellent Contented Dementia is the Michelin, then this is a useful companion volume. Neither of these books present doom and gloom. Law quotes Alice Thomas Ellis: ‘I make it my business to be happy. Life is bloody awful enough without being unhappy.’