The document provides guidelines for selecting consultants using different selection methods including single-source selection, quality- and cost-based selection, consultants' qualifications selection, and least-cost selection. It discusses circumstances where single-source selection may be appropriate and guidelines for selecting different types of consultants such as UN agencies, NGOs, procurement agents, inspection agents, banks, auditors, and service delivery contractors. The guidelines aim to ensure economy, efficiency, equal opportunity, and transparency in the selection of consultants.