The legally secure application of the "Fee Structure for Architects and Engineers" (HOAI) is crucial for both clients and contractors to accurately describe, price, and settle contracts for architectural and engineering services. With the HOAI 2021, the fee calculation has fundamentally changed, for example, through the abolition of maximum and minimum rates and the introduction of free negotiability of services and fees. The HOAI now serves only as a guideline. This book supports you in contract initiation, contract execution, and provides comprehensive information on the innovations of the HOAI regarding fee issues. Contents: New legal basis for HOAI 2021, detailed regulations of HOAI 2021, fundamentals of architectural law, current construction contract law, digital extras: comprehensive architect contract template, new HOAI 2021.