This week's topic focuses on contractual arrangements in commercial projects. The objective is to have a broad understanding of commercial planning and projects. The readings include Peña-Mora F., Tamaki T., Kerzner, Law handbook, Wikipedia Australian Contract Law, PMBOK, and more. The summary of the text includes answers to questions posed in the lecture, such as the spectrum of contractual arrangements, legal conditions for a contract, type of contracts in the Channel Tunnel, benefits of formalization of the contract process, importance of the type of contract for governing contractor and buyer behaviors, and interaction between procurement processes and other knowledge areas.