A need is something that is necessary for organisms to live a healthy life. Needs are distinguished from wants because a deficiency would cause a clear negative outcome, such as dysfunction or death. Needs can be objective and physical, such as food, or they can be subjective and psychological, such as the need for self-esteem. On a social level, needs are sometimes controversial. Understanding needs and wants is an issue in the fields of politics, social science, and philosophy.

To most psychologists, need is a psychological feature that arouses an organism to action toward a goal, giving purpose and direction to behavior.

The most widely known academic model of needs was proposed by psychologist Abraham Maslow. In his theory, he proposed that people have a hierarchy of psychological needs, which range from security to self-actualization. However, while this model is intuitively appealing, it has been difficult to operationalize it experimentally. It was further developed by Clayton Alderfer.

Captain America is a fictional character, a superhero who appears in comic books published by Marvel Comics. The character first appeared in Captain America Comics #1 (cover-dated March 1941), from Marvel Comics' 1940s predecessor, Timely Comics, and was created by Joe Simon and Jack Kirby. As of 2007, an estimated 210 million copies of "Captain America" comic books had been sold in 75 countries. For nearly all of the character's publication history, Captain America was the alter ego of Steve Rogers, a frail young man who was enhanced to the peak of human perfection by an experimental serum in order to aid the United States war effort. Captain America wears a costume that bears an American flag motif, and is armed with an indestructible shield that can be thrown as a weapon.

An intentionally patriotic creation who was often depicted fighting the Axis powers of World War II, Captain America was Timely Comics' most popular character during the wartime period. After the war ended, the character's popularity waned and he disappeared by the 1950s aside from an ill-fated revival in 1953. Captain America was reintroduced during the Silver Age of comics when he was revived from suspended animation by the superhero team the Avengers in The Avengers #4 (March 1964). Since then, Captain America has often led the team, as well as starring in his own series.

Adam Richard Wiles (born 17 January 1984), better known by his stage name Calvin Harris, is a Scottish DJ, singer, songwriter, and record producer. His gold-selling debut album, I Created Disco, was released in 2007 and contained the top ten singles "Acceptable in the 80s" and "The Girls". His second studio album, Ready for the Weekend (2009), reached number one in the UK Album Chart and includes the chart-topper "I'm Not Alone", the UK top five hit "Ready for the Weekend", and the singles "Flashback" and "You Used to Hold Me".

A remix album titled L.E.D. Festival was released in July 2010 as a free album in the August issue of Mixmag. Harris is currently working on his third studio album—due for release in 2012—which has produced the singles "Awooga", "Bounce", "Feel So Close", and "Let's Go". He has written and produced records for other recording artists including Kylie Minogue, Sophie Ellis-Bextor, Dizzee Rascal, Rihanna (on the international chart topper "We Found Love"), and Kesha.