This book analyses the single-member limited liability company (Societas Unius Personae, SUP) proposed by the European Commission (COM[2014] 212). It concludes that the proposal has two serious weaknesses, namely the online formation with an unsafe proof of identity and the insufficient protection of creditors. To these are added the missed parallelism with applicable insolvency law because of the adoption of the incorporation theory as a connecting factor and - from a German perspective - the risk that the SUP be used as a tool for avoiding employees' codetermination. Furthermore, the SUP is largely unsuitable as a building block for corporate groups due to the non-regulation of the single-member's right to issue instructions and of directors' liability: as long as the right to issue instructions follows the non-harmonised laws of the Member State in which the SUP is registered and its exercise is possible only under the Damocles' sword of liability under national law, group parent companies have little incentive to run their subsidiaries in other EU countries as SUPs. The author proposes several improvements of the text. Dr. Peter Kindler is Professor of Corporate Law and Private International Law at the Ludwig-Maximilian-University of Munich.