"All by Myself" is a song by American singer-songwriter Eric Carmen, released by Arista in December 1975 as the first single from Carmen's debut album, Eric Carmen (1975). The verse is based on the second movement (Adagio sostenuto) of Sergei Rachmaninoff's 1900–1901 Piano Concerto No. 2 in C minor, Opus 18. The chorus was taken from the song "Let's Pretend", which Carmen wrote and recorded with the Raspberries in 1972.^[5] The slide guitar solo was performed by studio guitarist Hugh McCracken.^[6]

According to Carmen, he first wrote the solo part of the song, writing four bars at a time, eventually completed the interlude after two months.^[7] He needed to put this into a song, and after listening to Rachmaninoff's 2nd piano concerto, a piece famously used to underscore the 1945 British film Brief Encounter, he adapted the melody of its second movement to write the verse.^[7] Rachmaninoff's music was in the public domain in the United States at that time, so Carmen thought no copyright existed on it, but it was still protected outside the U.S. subsequent to the release of the album. He was later contacted by the Rachmaninoff estate and informed that it was protected.^[8] An agreement was reached in which the estate would receive 12 percent of the royalties from "All by Myself" as well as from "Never Gonna Fall in Love Again", which was based on the third movement from Rachmaninoff's Symphony No. 2.^[9][10]

Carmen stated that he also incorporated part of another melody into this song. The melody of the chorus was taken from his previous hit with the Raspberries, "Let's Pretend".^[7]

Carmen performed "All by Myself" and his follow-up hit, "Never Gonna Fall in Love Again", on The Midnight Special television program on July 23, 1976 (season 4, episode 37). The show was hosted by The Spinners.^[11]

The power ballad^[12] was the first single from Carmen's first solo LP after leaving the power pop group the Raspberries and was released in December 1975. Billboard described the song as "a superb rock ballad...faithfully capturing most of the good time feel in rock."^[13] Cash Box said that Carmen "captures the vocal power of at least two of the three Bee Gees and seems also to have tapped the lyric capabilities of a Paul McCartney."^[14] Record World said that Carmen "croons over a backdrop of cascading strings on this self-penned delight from his recent album."^[15]

It reached number two on the Billboard Hot 100; both "Love Machine" by The Miracles and "December 1963 (Oh, What a Night)" by The Four Seasons, kept the song from number one.^[16] "All by Myself" did reach number one on the Cash Box Top 100 Singles and number three in Canada. The single sold more than one million copies in the United States and was certified gold by the RIAA in April 1976.^[17] "All by Myself" was Carmen's first of eight US Top 40 hits. In the UK, however, this was his only Top 40 success, peaking at number 12. The song would be featured in an episode of the popular television series Friends during a scene of Chandler and Joey being depressed after Joey moves out.

The most notable cover version of "All by Myself" was recorded by Canadian singer Celine Dion in 1996. It was the fourth (or third, depending on the country) hit single from her fourth English-language studio album, Falling into You (1996).^[38] Produced by David Foster at Compass Point Studios in the Bahamas, it was released on December 9, 1996, in the United Kingdom and on March 11, 1997, in the United States.

The single became one of Dion's biggest hits in the United States, reaching number one on the Hot Adult Contemporary Tracks (for three weeks) and the Latin Pop Airplay (two weeks). It peaked at number four on the Billboard Hot 100 (number seven on the Billboard Hot 100 Airplay and number five on the Hot 100 Singles Sales). It was also a top 10 hit in France, United Kingdom, Wallonia in Belgium and the Republic of Ireland. In Canada, "All by Myself" was released as a promotional single only, hitting number one on the Adult Contemporary Chart. "All by Myself" was certified gold in the US (500,000) and in the UK (400,000) and silver in France (125,000).

During an interview on Watch What Happens Live with Andy Cohen, Dion revealed that the famous high note (F5) leading into the key change had not been planned but David Foster surprised her with it when she appeared for recording. When Dion asked why the surprise, Foster told her that if she couldn't sing it, other singers would, which prompted Dion to prove to Foster that she could sing it.^[39]

In 1994, "All by Myself" was covered by New Zealand singer Margaret Urlich. Her version reached number 100 in Australia in November 1994,^[98] and number 26 in New Zealand in March 1995.^[99]

In 2018, a cover by Ghian Wright, renamed to "I'm All Alone (Belter Version)", was used in the science fiction television series The Expanse, in the episode of season 3 "Delta-V".^[100] The lyrics of the song were rewritten in the mix of English and Belter Creole, a constructed language made for the TV series by Nick Farmer, that was used in the show by Belters, the inhabitants of the asteroid belt and outer planets.^[101][102] The lyrics were additionally adjusted to fit the in-universe setting^[102] The full version of the song was later placed on The Collector's Edition version of the TV series soundtrack, that was released on December 13, 2019.^[100]