2 Cool 4 Skool is the debut single album released by BTS on June 12, 2013 through Big Hit Entertainment and distributed by Loen. The album was supported by the singles "No More Dream" and "We Are Bulletproof Pt.2". Commercially, it peaked at number five on the Gaon Album Chart in South Korea, and at number ten on Billboard's World Albums Chart in the United States.

While billed as a single, the album boasts an impressive 27-minute runtime. This is the product of the firm conviction and passion of BTS that hip hop musicians must make their voices heard through their albums. Each member flexed their musical prowess by taking part in creating the lyrics and music for every song on the album. BTS has repeatedly said that “hip hop is genuine music for telling one’s own story,” and indeed the members rap about their own experiences and emotions. There is no discontinuity between the emotions and lyrics of BTS. The album is a satisfaction in both quality and quantity. 

O!RUL8,2? (Oh! Are you late, too?) is the first extended play by BTS. It was released on September 11, 2013 as the second album after 2 Cool 4 Skool. The album consists of ten tracks, with "N.O" (also known as "No Offense") as the lead single. The group later promoted "Attack On Bangtan (진격의 방탄)", another track from the album.

THE 1ST MINI ALBUM - With O!RUL8,2? (Oh! Are you late, too?), BTS offers the message that “you must find your happiness and your own life before it’s too late.”

Lyrics that brutally lay open reality as it is deliver a bold admonition to a world that inflicts despair. Children are raised as studying machines without a chance to think about the future.

A world where classmates are not friends but competitors trying to trample each other. BTS sings about the wounds and anguish that such hopeless life has left on today’s teens.

With their previous two albums, 2 COOL 4 SKOOL and O!RUL8,2?, BTS sang about the dreams and happiness of teens. The songs spoke about young people living without a dream and schools that force rigid and homogenous thought onto its students. The new album, released on February 12, continues to focus on school and teens. As hinted by the title, SKOOL LUV AFFAIR, the album’s main theme is the love that blossoms in the school. This album is a culmination of the “School Trilogy” project that discusses the topics of most interest to teens their own age—dreams, happiness and love. Such penetrating insight into the hearts and minds of young people led to the absolute support that BTS has received from fans their age. The members again directly participated in the making of the songs, vowing to ensure that the songs reflect the reality of the music fans of their own generation.

Source: Big Hit

In their first studio album in a year and two months, BTS sings about love gone awry in DARK & WILD. They warn the girl who acts like she doesn't love them not to test their love anymore.

The boys are no longer in their school uniforms. They have become tougher, singing that their love is not to be treated lightly. A year and two months into their debut, BTS made sure that the visuals, performance and all the elements of their first studio album are flawless. Tracks that highlight the different genres of hip hop—South, West, Boom Bap and Trap—provide a clear direction of BTS' music. The title track “Danger” is a tightly-composed hybrid hip hop song with a piercing punk-rock guitar sound that features stark rap, a powerful hook and exhilarating shouting.

Source: Big Hit