Before you go looking for the book about the specific hard feeling — the anger, the worry, the grief — start here, with the books that simply give your child the words. This is the entry point: the gentlest first picture books for naming feelings out loud and learning that all of them are okay to have. Pick one book by your child's age and reach for it on an ordinary calm day, not mid-meltdown. Every title does the same quiet thing — it names happy and sad and scared and mad, treats each as normal, and hands your child a vocabulary they'll use for years. Get these words in early, and every harder feelings book down the road has something to stand on.
This is a browse-by-age shelf and any one book is a good start — none builds on another, there's no reading order, so pick by how old your child is and what kind of book they like. For the very youngest, 'The Feelings Book' is flagged as the place to start: it's the simplest and silliest, one feeling and one funny picture per page, the easiest possible on-ramp. Right beside it for toddlers sit 'Lots of Feelings,' which uses photographs of real children's faces, and 'The Way I Feel,' which leads with big expressive faces and rhyme. For a child ready for a little more, 'In My Heart' and 'My Many Colored Days' are the loveliest and most poetic — feelings as body sensations and as colors — and both make gorgeous bedtime reads. 'Glad Monster, Sad Monster' is the hands-on, playful one, with punch-out masks to act each feeling out. 'The Color Monster' is the modern favorite, sorting tangled feelings into jars. And 'Listening to My Body' sits a step later, for the child who has the feeling words and is ready to notice where a feeling lives before it takes over. What every book shares is the same gentle move — it names the feeling, treats it as normal, and never once calls a feeling bad.