Azure Active Directory (Azure AD) is Microsoft's multi-tenant, cloud-based service, which blends directory services, application access management, and identity protection into a unified solution. It provides an extensive platform to manage user identities, perform access management, and implement security measures to safeguard business data.

Candidates skilled in Azure AD are capable of providing seamless access to applications within an organization's infrastructure, ensuring adherence to enterprise-level security policies. This skill can cover diverse tasks such as providing single sign-on (SSO) capabilities, multi-factor authentication, device registration, self-service passwords, role-based access control, and security reporting.

This skill is in high demand across businesses of all sizes to effectively manage and secure cloud resources. Employees skilled in Azure AD are likely to wield roles involving cloud application management, IT administration, and cybersecurity.

The foundational skills that are prerequisite to learning Azure AD can be categorized into three main areas:

1. General Understanding of Networking: Working with Azure AD demands a solid foundation in networking principles, internet protocols, and web technology.

2. Familiarity with Cloud Services: As Azure AD is a cloud-based solution, knowledge and understanding of cloud technology, specifically Microsoft Azure, is a significant advantage for candidates looking to specialize in Azure AD.

3. Knowledge of Identity Management: Basic awareness around concepts of identity management, user authentication, authorization, and security is necessary. A working proficiency in these areas can speed up the learning curve for mastering Azure AD.

With the increasing demand for cloud-based solutions, Azure AD remains an essential skill for candidates who are aiming for IT roles in modern-day companies. Learning Azure AD can open a myriad of opportunities in roles related to cloud administration and security management.