"Heavy" is the debut album by American psychedelic rock band Iron Butterfly, released in 1968. The album exhibits a more carefree and spontaneous sound compared to later releases, due to the group being less experienced at the time. The songs possess a bluesy, soulful feel, with gritty, expressive vocal performances and overly dramatic music arrangements. Although the group had a hard time matching the album's success in future offerings, "Heavy" became a template for Iron Butterfly's sound which was often imitated by countless other late '60s psychedelic bands. This album established Iron Butterfly's heavy, hard rock credentials, hence, setting a foundation for the band's most successful release, "In-A-Gadda-Da-Vida."
The original members consisting of Doug Ingle (vocals, organ), Jack Pinney (drums), Greg Willis (bass), and Danny Weis (guitar) had only been together for six months before recording their first album. Despite the members being all under 20 and inexperienced in the studio, the album was a showcase of their raw talent, and it was an album ahead of its time, having been released a year before the concept of 'heavy metal' was widely recognized. As the band's unique, heavy sound did not fit well with the music trends of that time, the album only reached Number 78 in the charts, but it served as an important stepping stone in their career, leading to significant success in the following years.