Book excerpt: The industry of management consulting is vast and extremely diverse. The scope of expertise and provisions encompassed by this designation is vast. The distinction between the work of the most expensive strategy agencies and that of a project management consultant is of such magnitude that the two may fail to identify one another as practitioners of the same field. Certain publications aim to discuss particular aspects of this industry. They frequently describe a variety of consulting instruments and methods. Knowing the most effective tools and techniques does not automatically transform one into an effective consultant, as their applicability is contingent upon specific circumstances. Regarding the provision of services to the client, national management consultancy institutes and professional associations, which are entrusted with and encouraged to uphold the utmost level of accountability, should prioritise accountability for the performance of management consultants in numerous respects. The consulting approaches and methodologies utilised for a wide range of management and business problems, organisations, and environments are detailed in this book. A vast array of consulting approaches, techniques, methods, modalities, and styles exist. This variety is among the most stimulating aspects of management consulting. This implies that even clients who possess highly specific issues and personalities can typically locate a consultant who is a good match for their organisation and persona. On the contrary, consulting also demonstrates specific shared principles and methodologies. Certain ones are indispensable and are employed by an overwhelming majority of consultants.