Senses Fail is an American post-hardcore band formed in Ridgewood, New Jersey, in 2001. Founded by vocalist Buddy Nielsen, drummer Dan Trapp, guitarists Garrett Zablocki and Dave Miller, and bassist James Gill (replaced by Mike Glita shortly after); the band has seen many lineup changes, with Nielsen being the only consistent member. The band has released eight studio albums, one live album, and several EPs.

Senses Fail's beginnings started in October 2001 after James "Buddy" Nielsen posted an advertisement on the Internet to recruit members for the band. The advertisement attracted attention from Garrett Zablocki, who then began writing with Nielsen. Later Zablocki contacted Dave Miller to join the band who also brought along his friend, James Gill. After a short time with another drummer the band came across Dan Trapp, who was only 14-years-old at the time. Before the band signed to Drive-Thru Records, James Gill was kicked out of the band due to irreconcilable differences; he was replaced by former Tokyo Rose drummer Mike Glita.

Nielsen explained the band name, stating: "In Hinduism, they believe that being alive is hell, and the only way to reach Nirvana is to ultimately have no attachments to anything. So, people go out and live in the middle of the woods and they don't eat and don't drink. They just meditate because they've reached such a high level where they're not attached to love, relationships or anything. And if you want to reach the highest level of being and see God, you have to have all your senses fail."

Under the guidance of their first manager and then local promoter, Heath Miller, the band built a local fan base by playing any gig they could find, from skate parks (Rexplex) and clubs such as Club Krome & to churches, they soon entered the studio and started to record. Their first release, From the Depths of Dreams, was a six-track EP that was originally released on ECA Records on August 16, 2002. It originally started as two three-song demo CDs, but was later joined together to make one release by producer John Naclerio. The independent release did very well and caught the attention of some record labels. They signed to Drive-Thru Records, and reissued their EP on April 29, 2003, with two extra tracks, remastering, and new cover art. The b-side "Bastard Son" was also recorded during this time. The release saw much success, and sold enough copies to peak at No. 144 on the Billboard chart. In support of the EP, Senses Fail toured with such bands as The Used, Millencolin, The Starting Line, and Drive-Thru labelmates Finch.

Senses Fail started working on their debut album, Let It Enfold You in April 2003. During this time, lead singer and songwriter Buddy Nielsen was 18–19 years old. They worked with producer Steve Evetts (Saves the Day, A Static Lullaby, Every Time I Die) on their new label Vagrant Records. The lyrics were derived from a wide variety of sources. The title of the album was taken from a poem written by Charles Bukowski, the song "Irony of Dying on Your Birthday" is about the work of mythologist Joseph Campbell, and parts of the song "Slow Dance" include lines of the Dao De Jing. Nielsen stated that, "We just love making music and writing good songs. I feel like I've got a lot more to say and we've got a lot more to contribute. But even if things ended tomorrow, we've gotten 10 times further than we ever expected to get and that makes us feel like we've succeeded regardless of what happens from here on." Let It Enfold You was released on September 7, 2004, on Vagrant and Drive Thru Records. The album was certified gold by the RIAA, and has sold over 600,000 copies worldwide.

Let It Enfold You saw the release of two singles: "Buried a Lie" and "Rum Is for Drinking, Not for Burning." The music video for "Buried a Lie" was filmed on the set of the soap opera Guiding Light. Nielsen's mother, who shot the video, used to act in the show. The release of the video started attracting mainstream success for the band. During this period, Senses Fail were featured in magazines such as Kerrang!, Rolling Stone, Spin and appeared on the cover of Alternative Press.

The band toured extensively in support of the release. They were added to Warped Tour in 2004, 2005, and 2006, and 2009, and played on the main stage for the 2005 and 2006 editions of the tour. They were also included on the first Taste of Chaos tour in 2005 with such notable acts as The Used, My Chemical Romance, and Killswitch Engage. They also headlined a few tours of their own during this time with The Early November from Drive Thru and Emanuel from Vagrant.

The band performed on Conan O'Brien's show in early 2005. Nielsen forgot the lyrics to the first verse of "Rum is for Drinking, Not for Burning" during this performance due to a panic attack.