The Automotive Industry Guideline on REACH 4.0 is a comprehensive document developed by the automotive industry to provide guidance on compliance with the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation. The guideline covers important dates and deadlines, the registration process for substances and mixtures used in industrial processes, authorisation procedures, and notification requirements for substances in articles. It also provides advice on roles in the supply chain, REACH scope and exemptions, substance inventory, and downstream user obligations. The guideline includes a 5-step REACH compliance schedule and a list of ECHA guidance documents. The Automotive Industry Guideline is an essential resource for companies in the automotive industry to ensure compliance with REACH regulations.