The research aimed to analyze and test the relationship between the audit firm reputation and the degree of its industrial specialization, and the extent to which there is an effect of the audit client's industry characteristics as Moderator variables for this relationship, which are the degree of concentration, the level of homogeneity, the degree of accounting complexity.Based on a sample of companies listed on the Egyptian Stock Exchange for the year 2020, 145 observations were extracted, each observation represents; the proxy of audit firm reputation, the level of its industrial specialization, and the measures of the characteristics of Audit Client's Industry. The research concluded that there is a significant effect of the audit firm reputation on the degree of its industrial specialization.The research also concluded that the degree of accounting complexity only leads to a fundamental difference in the impact of the reputation of the accounting and auditing firm in Egypt on the degree of its industrial specialization. While it was not found that there was no effect of the difference in the degree of concentration of the audit client industry, or the level of homogeneity in the audit client industry.

The research aimed to study and analyze the technical features of the fourth industrial revolution and its professional repercussions on accounting and auditing, in order to explore the extent to which external auditors in Egypt are aware of the challenges facing the profession in light of the fourth industrial revolution and the repercussions it imposes on the foundations of the profession in terms of; practical and professional qualifications of auditors, auditing approach, organization the auditing profession, and the model of external auditing of financial statements represented in its four phases, which are; agreeing the terms of audit engagements, audit planning, obtaining and evaluating audit evidence, and forming an opinion and reporting.By conducting an exploratory study on a random sample of 25 auditors in Accountability State Authority and 38 auditors in Audit Firms, the research concluded that there is an awareness of the repercussions of the Fourth Industrial Revolution on External auditing as an integrated professional service, with no significant differences between the awareness of the members of the exploratory study sample of Audit Firms' auditors and Accountability State Authority' auditors about the repercussions of the fourth industrial revolution on external auditing as an integrated professional service.

The research aimed to study and test the effect of the different External Audit's Approaches on the level of readability in the audit reports, especially "the basis of modified opinion's paragraph", "Emphasis of Matter" or "Other Matter" Paragraphs, that the auditor can write without restrictions from Standards forms. The number of words, the number of financial Terminologies, and the average length of sentence have been used as proxies to measure the level of readability of an audit report paragraphs subject to test. Based on a sample of companies listed on the Egyptian Stock Exchange over the period from 2014 to 2019, the research concluded that it is relatively difficult to read "basis of modified opinion paragraph" under dual audit approach, if compared with similar reports, according to single or joint audit approach. On the other hand, the research concluded that it is relatively easy to read "Emphasis of Matter" or "Other Matter" Paragraphs under joint audit approach, if compared with similar reports, according to single or dual audit approach.