This work provides a comprehensive overview of the entire law governing stock corporations (AG), European companies (SE), and limited liability companies (GmbH), including transformation and group law as well as insolvency law references. The parallel presentation of GmbH and AG, highlighting their similarities and differences, enhances the understanding of the fundamental structures and facilitates the comprehension of corporate law, which is essential in practical design contexts. The work takes into account current case law as well as the latest legislative developments in corporate law and capital market law, including the 2016 Stock Corporation Law Reform, the new regulations of the Money Laundering Act, the implementation of the CSR Directive, and the 2nd Financial Market Regulation Act (FinMaNoG).