This book is the result of the practical analysis carried out during 2015 and 2016 for the preparation of a Master's thesis on Auditing at the University of Alcalá (UAH). By means of the Resolution of 15 October 2013 of the Spanish Accounting and Auditing Institute (ICAC), the new Technical Auditing Standards were published. Within the previous body of standards is ISA-ES 600 "Special Considerations - Audits of Group Financial Statements (Including the Work of Component Auditors)", which will be the focus of this paper. Some of the issues addressed in this study are: the case studies applicable in situations where there is a change of auditors; the steps to be followed when issuing opinions on consolidated financial statements and there are different auditors in the audited group; joint audit situations and responsibility in the audit report.