The Nocturnal Brain by Guy Leschziner review – bizarre sleep stories

From eating and motorbike riding while asleep to corks in the bed as a cure for restless legs – a neurologist’s casebook

What Dementia Teaches Us about Love by Nicci Gerrard review – savage realities

A powerful and beautifully written account, centred on the experience of the author’s father, and identifying a crisis in care

The best form of self-help is … a healthy dose of unhappiness

We’re more likely to find solace by accepting reality rather than in positive thinking, says author Tim Lott

Good Reasons for Bad Feelings review – a new approach to mental disorder

Randolph Nesse’s insightful book suggests that conditions such as anxiety and depression have a clear evolutionary purpose

Nicci Gerrard: ‘Dementia is more scary when you try not to think about it’

The Observer journalist on her father’s dementia, caring for campaigners, and facing her fears in her new book

What will you be reading next year? London book fair’s star attractions

Salman Rushdie’s take on Don Quixote, Elton John’s memoirs and a study of criminals in Broadmoor – a selection of the biggest and most interesting books announced at the fair

Stressed Brits buy record number of self-help books

Bookshop owners say political turmoil has sent customers in search of uplifting titles

Four Words for Friend by Marek Kohn review – why language matters more than ever

Is the British reluctance to learn languages partly to blame for Brexit? The case for multilingualism

Move over, mindfulness: it’s time for ‘finefulness’

After endless guides to self-help, a new wave of books spearheaded by The Little Book of Bad Moods is switching the focus to more realistic hopes

Making Evil by Julia Shaw review – the ‘science’ behind humanity’s dark side

Does evil exist? Are we all born killers, saved only by impulse control? A chattily written study of inexcusable acts