Modality has two main types, deontic and epistemic. However, our article only deals with epistemic. English modality's realizations are very broad, including all word-forms adjective, adverbs, verbs, nouns and a number of subordinate clauses. Yet, we only consider it in the first four word-forms. The data is based on the utterances in conversations among characters in "The Thorn Birds" written by an Australian writer, Colleen McCullough. We find that nowhere is better for the characters to express their feelings and attitudes toward every incident than in conversations which are reliable source of data for modality in general and epistemic in particular. The article also indicates the obstacles of the learners in applying "modal verbs" properly to express their own thinking, thereby giving some causes and solutions to ensure effective conversations