Background: Bakhtin was born in Oryol, Russia, to an old family of the nobility. His father was the manager of a bank and worked in several cities. For this reason Bakhtin spent his early childhood years in Oryol, in Vilnius, and then in Odessa, where in 1913 he joined the historical and philological faculty at the local university (the Odessa University). Katerina Clark and Michael Holquist write: "Odessa..., like Vilnius, was an appropriate setting for a chapter in the life of a man who was to become the philosopher of heteroglossia and carnival.
Context: The Dialogic Imagination (first published as a whole in 1975) is a compilation of four essays concerning language and the essay: "Epic and Novel" (1941), "From the Prehistory of Novelistic Discourse" (1940), "Forms of Time and of the Chronotope in the Novel" (1937-1938), and "Discourse in the Novel" (1934-1935). It is through the essays contained within The Dialogic Imagination that Bakhtin introduces the concepts of heteroglossia, dialogism and chronotope, making a significant contribution to the realm of literary scholarship. Bakhtin explains the generation of meaning through the "primacy of context over text" (heteroglossia), the hybrid nature of language (polyglossia) and the relation between utterances (intertextuality). Heteroglossia is "the base condition governing the operation of meaning in any utterance." To make an utterance means to "appropriate the words of others and populate them with one's own intention." Bakhtin's deep insights on dialogicality represent a substantive shift from views on the nature of language and knowledge by major thinkers such as Ferdinand de Saussure and Immanuel Kant.  In "Epic and Novel", Bakhtin demonstrates the novel's distinct nature by contrasting it with the epic. By doing so, Bakhtin shows that the novel is well-suited to the post-industrial civilization in which we live because it flourishes on diversity. It is this same diversity that the epic attempts to eliminate from the world. According to Bakhtin, the novel as a genre is unique in that it is able to embrace, ingest, and devour other genres while still maintaining its status as a novel. Other genres, however, cannot emulate the novel without damaging their own distinct identity.  "From the Prehistory of Novelistic Discourse" is a less traditional essay in which Bakhtin reveals how various different texts from the past have ultimately come together to form the modern novel.  "Forms of Time and of the Chronotope in the Novel" introduces Bakhtin's concept of chronotope. This essay applies the concept in order to further demonstrate the distinctive quality of the novel. The word chronotope literally means "time space" (a concept he refers to that of Einstein) and is defined by Bakhtin as "the intrinsic connectedness of temporal and spatial relationships that are artistically expressed in literature." For the purpose of his writing, an author must create entire worlds and, in doing so, is forced to make use of the organizing categories of the real world in which he lives. For this reason chronotope is a concept that engages reality.  The final essay, "Discourse in the Novel", is one of Bakhtin's most complete statements concerning his philosophy of language. It is here that Bakhtin provides a model for a history of discourse and introduces the concept of heteroglossia. The term heteroglossia refers to the qualities of a language that are extralinguistic, but common to all languages. These include qualities such as perspective, evaluation, and ideological positioning. In this way most languages are incapable of neutrality, for every word is inextricably bound to the context in which it exists.
Question: Why did he publish the four essays together.
Answer: It is through the essays contained within The Dialogic Imagination that Bakhtin introduces the concepts of heteroglossia, dialogism and chronotope,

Background: William Taylor (July 24, 1921 - December 28, 2010) was an American jazz pianist, composer, broadcaster and educator. He was the Robert L. Jones Distinguished Professor of Music at East Carolina University in Greenville, and from 1994 was the artistic director for jazz at the John F. Kennedy Center for the Performing Arts in Washington, D.C. A jazz activist, Taylor sat on the Honorary Founders Board of The Jazz Foundation of America, an organisation he started in 1989, with Ann Ruckert, Herb Storfer and Phoebe Jacobs, to save the homes and the lives of America's elderly jazz and blues musicians, later including musicians who survived Hurricane Katrina. Taylor was also a jazz educator, who lectured in colleges, served on panels and travelled worldwide as a jazz ambassador.
Context: Taylor was born in Greenville, North Carolina, but moved to Washington, D.C., when he was five years old. He grew up in a musical family and learned to play different instruments as a child, including guitar, drums and saxophone. He was most successful at the piano, and had classical piano lessons with Henry Grant, who had educated Duke Ellington a generation earlier. Taylor made his first professional appearance playing keyboard at the age of 13 and was paid one dollar.  Taylor attended Dunbar High School, the U.S.'s first high school for African-American students. He went to Virginia State College and majored in sociology. During his time he joined Kappa Alpha Psi fraternity. Pianist Undine Smith Moore noticed young Taylor's talent in piano and he changed his major to music, graduating with a degree in music in 1942.  Taylor moved to New York City after graduation and started playing piano professionally from 1944, first with Ben Webster's Quartet on New York's 52nd Street. The same night he joined Webster's Quartet, he met Art Tatum, who became his mentor. Among the other musicians Taylor worked with was Machito and his mambo band, from whom he developed a love for Latin music. After an eight-month tour with the Don Redman Orchestra in Europe, Taylor stayed there with his wife, Theodora, and worked in Paris and the Netherlands.  Taylor returned to New York later that year and cooperated with Bob Wyatt and Sylvia Syms at the Royal Roost jazz club and Billie Holiday in a successful show called Holiday on Broadway. A year later, he became the house pianist at Birdland and performed with Charlie Parker, J.J. Johnson, Stan Getz, Dizzy Gillespie and Miles Davis. Taylor played at Birdland longer than any other pianist in the history of the club. In 1949, Taylor published his first book, a textbook about bebop piano styles.
Question: Did he continue to play professionally?
Answer:
started playing piano professionally from 1944, first with Ben Webster's Quartet on New York's 52nd Street.