Genuine texts vary in communicative aims, in their topics, in length, structure and composition to such extent that it is difficult to give the concept of 'text' a generalizing and precise definition. In the book "Text as an Object of Linguistic Study" Prof. Galperin offers his definition of the 'text' in which he tries to differentiate 'text' as a speech product, that is presented in a written form, from 'discourse' as a piece of oral speech. He writes: 'Text is a piece of speech production represented in a written form that correlates to some literary norms; it is characterized by completeness, wholeness and coherence and consists of specific text units joined by various logical, lexical, grammatical and stylistic means under one title; it has a definite communicative aim as a carefully thought-out-impact on the reader' (Гальперин И. P. Текст как объект лингвистического исследования. - М. 1981. - С. 18)
This definition contains the most general parameters of well-composed texts and states knowledge about text formation as an object of special linguistic interest. Prof. Galperin proposes to study text categories and singles out some ten categories in his book. Categories of discreteness (divisibility), cohesion are referred mainly to basic structural categories and basic semantic categories are informativeness, continuum, prospectively and retrospection, semantic independence of its constituents, modality, integration and completeness.
Well-formed texts undoubtedly follow a certain compositional pattern: there is a heading, the text as such and conclusion. The text itself can be divided into smaller units made up of interdependent sentences, that are grouped into a paragraph, then there may be chapters, parts and books. This kind of pragmatic division which aims at promoting the process of comprehension varies from text to text, as the author always takes into consideration information capacity of human brains.
Any reader perceives a text in his individual manner. It depends upon his approach, his aim, his intellect and his emotional susceptibility. One may either read merely for the sake of the plot or grasp all the subtleties of the text and penetrate deep into the author's intention. To achieve the latter a text must be treated as an integral whole. To comprehend a text as an integral whole, the reader must perceive simultaneously its several layers, as a text is to be regarded as a hierarchy of them in mutual interdependence and interpenetration.
(Шаховский, В. И. Стилистика английского языка / В. И. Шаховский. - М. : ЛКИ, 2008. - С. 132) -