One of the distinguishing features of the forms of contract developed by the professional institutions in the UK for the carrying out of building or civil engineering works and the supply and installation of mechanical and electrical plant is the role given to the architect/engineer. From even a cursory look at the sets of contract conditions, it is apparent that in some ways the architect/engineer is, in a sense, an additional party to the contract along with the employer and the contractor. In other forms of contract a project manager is appointed who may be either an individual or a company but who again is in some senses a third party to the contract with authority to issue instructions and certificates which are binding upon the employer unless challenged at adjudication/arbitration or in litigation. In the first instance attention will be focused upon the architect/engineer and the position of the project manager will be examined later. Why is there need for an appointment of an architect/engineer, what is its contractual significance, and how in practice does it work?