The best children's books are also the saddest I then take him upstairs to have his bedtime story. What do you want? I ask him "Peepo," he says. You always want Peepo. You sure you don't want anything different? "Peepo!" he demands. As he is still in a strange mood, I agree to Peepo. On the surface, this wonderful book is a jolly day-in-the-life tale of a baby. We see what the little boy sees, from when he wakes up in his cot to when he is tucked up in bed at night: his mother pouring hot porridge in a bowl, his sisters squabbling, his ball, his teddy. All very charming. But it is shot through with a profound sadness; not the words, the pictures. Set during the War, the mother is careworn and perpetually tidying their modest suburban home, while as the day progresses the father, on leave, appears to be readying himself to return to the front. In the final picture, the family are all together, happily kissing the baby goodnight. But you are left in little doubt that the father, uniform on and kitbag slung over his shoulder, might be kissing the baby goodnight for the final time. It's an utterly beautiful book, with evocative period details in every illustration: the barrage balloon above the park and a ration book on the kitchen table, for example. But the cadences of the story descend ever downwards. The potential heartbreak is clearly there. The Human Furby, of course, is oblivious to this melancholia. He just loves shouting "Peepo!" at every turn of the page. One of the joys of being a parent has been to discover an entire body of literature that had yet to be written when I was a child. I am too old to have known Janet & Allen Ahlberg first time around (and the fact that I know Janet, the illustrator, died at just the age of 50 somehow exacerbates the sorrow underlying Peepo). I grew up with Roald Dahl, who created a universe where hardly any emotionally functioning adults were allowed to survive. James (of peach fame), the unnamed Witches narrator, Sophie (of BFG) are all orphans. Danny's mother is dead. This tradition has been continued by the next generation of authors. Judith Kerr ruthlessly killed off Mog and Michael Rosen's 'Sad Book' is tears-streaming-down-your-face traumatic. ["What makes me most sad is when I think about my son Eddie. He died. I loved him very, very much but he died anyway."] These two fabulous books are written specifically to tackle grief. But the ones I find saddest are those laced with a quiet anguish, such as 'Not Now, Bernard', which is about a boy ignored by his parents, who always snap: "Not now, Bernard," as they shoo away their son. So preoccupied are the mother and father, they fail to realise when he is eaten up by a monster, who proceeds to take Bernard's place in the home. Even as they turn the lights out in the boy's room they fail to notice it is not their son, but a confused monster, in the bed. Maybe it is perverse of me, but I rather like how many books still dole out the pain. Too much of modern childhood has had the rough edges sanded down. I can't stand how Humpty Dumpty is now invariably put together again in modern tellings, and how hi-viz tabards have replaced the school uniform on trips out. Emotional heartache is part of childhood. I'm glad it hasn't been completely airbrushed out of fiction. Dad of Four is a weekly column by feature writer Harry Wallop for Telegraph Men. To read more from the series, try one of the below: My daughter knows about my affair - Why you should never meet your toddler's idols - Dad of four: it's the end of the primary school era - How to make money off children at a summer fête - Why is there no competition in Sports Day? - The best travel products for children that every parent needs