Young Adult fiction is the ultimate crossover category. While it's intended for people below the age of 18, over half of its readers are actually older. This publishing category has become increasingly lucrative over the past few years and, far from the days of cheesy romances, it finds itself with a mass of skilful writers who tackle real issues (mental health, sexuality, drug addiction) that young people are facing now. The category is also leading the way for diversity in literature with a broad representation of race, class and gender being a defining feature of contemporary YA fiction.

This year the Book Festival has appearances and events from a number of big names in the Young Adult publishing category. Holly Bourne, best-selling British author of The Spinster Club series discusses her new book, Are We All Lemmings and Snowflakes?. Her works deal with topics from feminism to mental health, while Juno Dawson (novelist, Stonewall activist and proponent for LGBTQ+ representation in literature) talks about her new publication Clean, an honest portrayal of a girl battling with a heroin addiction.

Another writer who deals with drug addiction in his work is the legendary Melvin Burgess. Known as one of the pioneers of Young Adult Fiction, Burgess is a Carnegie Medal-winning author and has over 20 novels under his belt. His first book, 1996's Junk (its US title was Smack), encouraged literature for young people to focus on hard-hitting, difficult issues and, with its focus on drug-addicted teenagers, was highly controversial at the time. Brian Conaghan also dealt with tough subject matter in his 2014 novel When Mr Dog Bites (featuring a lad with Tourette's), while his new book, The Weight of a Thousand Feathers, portrays a boy who has to look after his sick mum while simultaneously trying to be a regular teenager.

Fans of YA fantasy fiction will be pleased with appearances from Marcus Sedgwick, author of the Raven Mysteries, and the Elf Girl & Raven Boy series, and the proud owner of many literary prizes. Here, he presents his new title, The Monsters We Deserve, a dark read about imagination. They will also be excited by an event with Alice Broadway, one of the best-selling YA writers of last year, who earlier this year released Spark, the sequel to her successful female-led fantasy, Ink. This time the main character Leora questions her own identity and sense of belonging.

Another interesting offering in the programme comes from Lin Man-Chiu, a best-selling Taiwanese children's author, whose work The Ventriloquist's Daughter is a scary piece about a nightmarish doll. And Cathy Forde, writer of the much-loved novel Fat Boy Swim, the story of an overweight child who overcomes bullies, will chat about her book being adapted into a musical theatre piece by Visible Fictions. As an added treat, scenes and musical numbers will also be performed.

Alice Broadway and LJ MacWhirter, 11 Aug, 6.30pm, £5.
Lin Man-Chiu and Paul Magrs, 13 Aug, 6.15pm, £5.
Holly Bourne and Cat Clarke, Spark Theatre, George Street, 16 Aug, 5.30pm, £5.
Juno Dawson, Spark Theatre, George Street, 17 Aug, 5.30pm, £5.
Brian Conaghan and Karmele Jaio, 19 Aug, 5pm, £8 (£6).
Melvin Burgess and Steven Camden, 22 Aug, 5.45pm, £5.
Cathy Forde, 24 Aug, 6.30pm, £8 (£6).
Marcus Sedgwick and Frances Hardinge, 26 Aug, 11am, £5.

All events at Charlotte Square Gardens unless stated, 0345 373 5888.