A consultant (from Latin: consultare 'to deliberate') is a professional (also known as Expert, Specialist, see variations of meaning below) who provides advice and further purposeful activities in an area of specialization. Definition and distinction Consultant Peter Block defines a consultant as 'someone who has influence over an individual, group, or organization, but who has no direct authority to implement changes'. He contrasts this with a surrogate manager, who is a person who 'acts on behalf of, or in place of, a manager'. The key difference is that a consultant never makes decisions for the individual or group, whereas a surrogate manager does make decisions. Consultancy UK defines the role as providing 'professional or expert advice in a particular field of science or business to either an organisation or individual'. The Harvard Business School provides a more specific definition of a consultant as someone who advises on 'how to modify, proceed in, or streamline a given process within a specialized field'. In his book, The Consulting Bible, Alan Weiss defines that 'When we [consultants] walk away from a client, the client's conditions should be better than it was before we arrived or we've failed. ' There is no legal protection given to the job title 'consultant'. = Subject-matter expert (SME) vs. Consultant =According to Institute of Management Consultants USA, 'The value of a consultant [as compared to a Subject-matter expert (SME)] is to be able to correctly diagnose and effectively transform an often ill-defined problem and apply information, resources and processes to create a workable and usable solution. Some experts are good consultants and vice versa, some are neither, few are both. ' Another differentiation perspective would be that a consultant sells advice, but an expert sells his expertise, or of Consultants vs. Coaches or SMEs vs. Team Leaders.