An advertising agency or ad agency is a service business dedicated to creating, planning and handling advertising (and sometimes other forms of promotion) for its clients. An ad agency is independent from the client and provides an outside point of view to the effort of selling the client's products or services. An agency can also handle overall marketing and branding strategies and sales promotions for its clients.

Typical ad agency clients include businesses and corporations, non-profit organizations and government agencies. Agencies may be hired to produce television commercials and radio commercials as part of an advertising campaign.

The first acknowledged advertising agency was William Taylor in 1786. Another early agency, started by James 'Jem' White in Fleet Street, London, in 1800, eventually evolved into White Bull Holmes, a recruitment advertising agency, that went out of business in the late 1980s. In 1812 George Reynell, an officer at the London Gazette, set up another of the early advertising agencies, also in London. This remained a family business until 1993, as 'Reynell & Son,' and is now part of the TMP Worldwide agency (UK and Ireland) under the brand TMP Reynell. Another early agency that traded until recently, was founded by Charles Barker, and the firm he established traded as 'Barkers' until 2009 when it went into Administration.

Derren Victor Brown (born 27 February 1971) is an English illusionist, mentalist, painter, writer and sceptic. He is known for his appearances in television specials, stage productions, photographic memory, and British television series such as Trick of the Mind and Trick or Treat. Since the first broadcast of his show Derren Brown: Mind Control in 2000, Brown has become increasingly well known for his "mind-reading" act. He has written books for magicians as well as the general public. His caricature artwork has received gallery exhibition and is available in a single volume documenting his portrait collection.

Though his performances of mind-reading and other feats of mentalism may appear to be the result of psychic or paranormal practices, he claims no such abilities and frequently denounces those who do. Brown states at the beginning of his Trick of the Mind programmes that he achieves his results using a combination of "magic, suggestion, psychology, misdirection and showmanship". Using his knowledge and skill, he appears to be able to predict and influence people's thoughts with subtle suggestion, manipulate the decision-making process and read the subtle physical and psychological signs or body language that indicate what a person is thinking.

Leo Burnett (October 21, 1891 – June 7, 1971) was an advertising executive and was one among of the most 'creative' men in the advertising business. The 19th Century was dominated by the copy-heavy ads with lengthy product descriptions and selling arguments, however, he developed fresh simple icons that came to symbolize easy-to-understand product benefits for the 20th-century consumer. He was known for being heavily involved in the Creative Revolution in the 1960s, with other great advertising heads like David Ogilvy, William Bernbach and Mary Wells. Burnett was named by Time Magazine as one of the 100 most influential people of the 20th century.

Born in St. Johns, Michigan, his parents were Noble and Rose Clark Burnett. His father ran a dry goods store and as a youth, Burnett worked with his father in the store. He grew up watching his father designing ads to promote his business. During high school, he worked as a reporter for a local, rural newspaper in the summers. After high school he went to study journalism at the University of Michigan and received his Bachelor's degree in 1914. His first job was as a reporter at the Peoria Journal in Peoria, Illinois. After realizing the future growth possibilities in advertising, he moved to Detroit in 1917, and he got a job editing an in-house publication for Cadillac dealers called Cadillac Clearing House as a copywriter. He successfully went on to become an advertising director for the company.