The brief is much more than a list of requirements - there is the whole question of the culture and personality of the company and its management style.

Brief Content - A detailed job description, which adequately describes the extent of the position and the challenges of the role, ie underperforming, difficult customers, need for more customers, etc are all key ingredients if we are to find the right individual.
The personality and educational/capability profile is also important. This will often develop into a wish list of must have and would like qualities or skills.

Client Briefing - For practical reasons, the vacancy brief can be taken over the telephone. This is an expedient solution and gets things moving, but a much better method would be a meeting, This is particularly necessary for specialist roles or awkward assignments. A meeting affords us an opportunity to get to know you and your requirements, which helps our selection process.