The toughest fighter is back in the second installment of Cythnia Lenor Garza's Lucia the Luchadora series (Penguin Random House), and she's dealing with her toughest enemy yet: a pesky little sister. Lucia is furious when her younger sibling Gemma rips a hole in her fighter mask, but her fury fades when she realizes her mask is missing and Gemma is the only one who can help her get it back. The Big of your family could learn a thing or two from Lucia and Gemma, a pair who realize they're stronger together than they ever are apart.

Lilly, of Lilly's Purple Plastic Purse fame, isn't too fond of her new brother Julius, rolling her eyes when her parents call him "the baby of the world." She makes a point of tormenting her unwelcome sibling, trying to scare him and even calling him "disgusting." Lilly plans for her loathing to be lifelong, until Cousin Garland starts making his own mean comments about Julius, and Lilly jumps to her brother's defense. Kevin Henkes's Julius, The Baby Of The World (HarperCollins) will show young readers the important role only a big sibling can play, giving your Big some motivation to bond with the invader in the crib.

Former foes turn allies in Lisa Mantchev's Jinx And The Doom Fight Crime! (Simon and Schuster), an imaginative story that will show big siblings that having a sidekick isn't so bad. Jinx and the Doom used to waste their time tussling each other, but they decide to use their powers for good to stop real enemies, like washing machines, godzilla, and more. This is a great one to add to your collection if your little ones have been at each other's throats lately.

First-time big siblings will relate to the many questions Diane Danzig answers in Babies Don't Eat Pizza (Penguin Random House), a go-to guide for adjusting to life with a new bundle of joy in the house. Whether your first-born is wondering what babies eat or why they have to sleep so much, Danzig has them covered, speaking to her readers in a lighthearted and matter-of-fact tone that gives older siblings the credit they deserve.

From the moment your kiddo hears the phrase "your baby" used in the text, they'll understand this new person belongs to them, too, bringing your family closer together.

Mercery Mayer's beloved Little Critter is off to a new adventure, and this one might be his toughest challenge yet: a little sister. The New Baby (Penguin Random House) shows Little Critter figuring out how to be the best big brother ever, mastering rocking his baby sis to sleep, pushing her stroller, and even changing her diapers. (A brave soul.) Think of the picture book as a way to get your child excited about all the fun ways they can help your family grow.

Parents have long had an abundance of guides to pregnancy, but no one had created a guide for siblings until Miranda Paul and Caldecott-honored illustrator Jason Chin teamed up on the brilliant Nine Months: Before A Baby Is Born (Neal Porter Books), out April 23. This picture book shows us the development of the baby alongside the family preparing to welcome its newest member — something sure to get a future Big excited.

Adjusting to life with a sibling can be tough, and Elmore Green is definitely having some growing pains in The New Small Person by Lauren Child, beloved for her descriptive illustrations. Elmore's unwelcome little sister starts touching all of his things, isn't a fan of favorite TV shows, and worst of all, it seems like everyone likes her better than him. All he wants is for life to go back to how it was before, until one fateful night.

Made for over-eager siblings-to-be who just can't wait for the new baby to arrive, Hello In There: A Big Sister's Book Of Waiting by Jo Witek might help your kiddo gain a little patience throughout your pregnancy, giving them ideas for how they can connect to your growing baby before they even come into the world. Plus, the book is oversized and interactive, so reading time has never been more fun.

Becoming a big brother is no easy feat, especially if you've never been one before. Help your little one prepare for what life will be like with a sibling by giving them the rundown on what exactly a big brother does in What Brothers Do Best (Chronicle Books) by Laura Numeroff, a charming story that sheds light on all the fun things you can do with a sibling. Whether you're climbing trees or making music, Numeroff shows readers that a sibling can be a built-in best friend.

Dot the bunny is anything but thrilled when her family adopts a wolf son — what if he eats everyone she loves? Dot's parents don't want to hear anything but praise for Wolfie, and she fears the worst. But when Wolfie's in danger, will Dot have a change of heart? Readers will relate to Ame Dyckman's Wolfie The Bunny (Hachette) no matter what their family looks like, and the heartwarming humor will be make your next story time a joy.

A go-to for parents expecting their second child, Joanna Cole's I'm A Big Sister (HarperCollins) is a catalogue of all the wonderful things Bigs can expect to become part of their lives once their sibling arrives. The simple and sweet story is full of earnest joy between brother and sister, which is all you could wish for your kids, right? Psst: the companion I'm A Big Brother is a hit too.

In Zoe's Room (No Sisters Allowed!) (Scholastic), Queen Zoe is dismayed when her parents have her younger sister Addie move into her room, ruining Zoe's perfect oldest kid kingdom full of tea parties and stargazing. She thinks nothing can change her mind, but then a thunderstorm shifts how she feels about her unwelcome roommate. Bethanie Murguia's tale of compromise and camaraderie might have your firstborn begging for bunkbeds.

Lottie's baby brother is in the background of this sweet story about a big sister who worries there are bad things under the surface of her local pool. As Lottie's mom totes about her little brother, Lottie discovers a new friend, Walter, who teaches her to have fun again.

A subtle and sensitive story from the author/illustrator behind the much-celebrated Florette, Lottie & Walter will show your Big how brave and grownup they are.

Available May 7 from Houghton Mifflin Harcourt.