Extraordinary transactions play an important role in the life of companies. The volume, which is intended as a guide for those who are faced with such transactions, is structured in six parts, one for each corporate transaction: transformation, merger, transfer, sale, demerger and liquidation. Within each part, the author, after having briefly analyzed the characteristics of the operation, sets out the statutory obligations and the rules governing proper bookkeeping. Great importance is then given to the exposure of fiscal discipline. Furthermore, particular attention is paid to jurisprudence and administrative provisions. The thirty-seventh edition updated the volume with the most recent regulatory and interpretative interventions both at civil and tax level. We also proceeded to provide some observations on the subject of IAS / IFRS accounting principles to be applied to extraordinary transactions.