Fantasy & Science Fiction:
* The Chronicles of Narnia by C.S. Lewis: A classic series about a group of children who travel to a magical land called Narnia.
* The Percy Jackson & the Olympians series by Rick Riordan: A fun and action-packed series about a teenager who discovers he is the son of Poseidon.
* The Ranger's Apprentice series by John Flanagan: This series follows Will, a young boy who becomes an apprentice to a Ranger.
* The Hobbit by J.R.R. Tolkien: A beloved story about a hobbit who goes on an adventure to reclaim a lost treasure.
* The Spiderwick Chronicles by Tony DiTerlizzi and Holly Black: A series about three siblings who discover a field guide to fairies.
* The Hunger Games by Suzanne Collins (though some might consider this bordering on mature themes): A dystopian series about teenagers forced to fight to the death.
Contemporary & Realistic Fiction:
* The Hate U Give by Angie Thomas: A powerful story about a teenage girl who witnesses the fatal shooting of her best friend by a police officer.
* The Book Thief by Markus Zusak: A historical fiction novel narrated by Death about a young girl who steals books during World War II.
* The Absolutely True Diary of a Part-Time Indian by Sherman Alexie: A humorous and moving story about a Native American boy who leaves his reservation to attend an all-white high school.
* Stargirl by Jerry Spinelli: A heartwarming story about a unique and unconventional girl who makes a big impact on her high school.
* Eleanor & Park by Rainbow Rowell: A sweet and romantic story about two teenagers who find love in a small town.
* The House on Mango Street by Sandra Cisneros: A coming-of-age story about a young Latina girl growing up in Chicago.
* A Wrinkle in Time by Madeleine L'Engle: A science fiction novel about a girl who travels through time and space to rescue her father.
Historical Fiction:
* Number the Stars by Lois Lowry: A story about a young girl who helps a Jewish family escape Nazi-occupied Denmark.
* The Boy in the Striped Pajamas by John Boyne: A heartbreaking story about the friendship between a young boy and a Jewish boy in a concentration camp.
* Roll of Thunder, Hear My Cry by Mildred D. Taylor: A powerful story about a black family in Mississippi during the Jim Crow era.
Other Recommendations:
* The Giver by Lois Lowry: A dystopian novel about a boy who learns about the truth of his seemingly perfect world.
* Matilda by Roald Dahl: A classic story about a young girl who loves to read and uses her intelligence to stand up to her cruel parents.
* Where the Red Fern Grows by Wilson Rawls: A heartwarming story about a boy and his two hunting dogs.
* Bridge to Terabithia by Katherine Paterson: A story about two children who create a magical world in the woods.
This list is just a starting point. There are many other great young adult books out there that are appropriate for all ages. Remember to check the book's description or review to make sure it fits your preferred reading level and content.