The head of the Second Backward Classes Commission was B.P. Mandal.

**Background:**
The Second Backward Classes Commission, also known as the Mandal Commission, was established in India in 1979. Its primary purpose was to identify the socially and educationally backward classes of India and recommend measures to improve their status.

**B.P. Mandal:**
B.P. Mandal, also known as Bindheshwari Prasad Mandal, was an Indian politician and a member of the Indian Parliament. He was appointed as the chairman of the Second Backward Classes Commission by the Indian government in 1978.

**Mandal Commission's Report:**
Under the leadership of B.P. Mandal, the commission submitted its report in 1980. The report identified a total of 3,743 castes and communities as socially and educationally backward classes (SEBCs). It recommended that 27% of government jobs and educational opportunities should be reserved for SEBCs to ensure their representation in public institutions.

**Implementation of Mandal Commission's Recommendations:**
The recommendations of the Mandal Commission report were implemented by the Indian government in 1990 through the implementation of the Mandal Commission Reservation Policy. This policy introduced a 27% reservation for SEBCs in government jobs, educational institutions, and other public sectors.

**Impact and Controversy:**
The implementation of the Mandal Commission's recommendations had a significant impact on Indian society. It provided opportunities for previously marginalized communities to access education and employment. However, it also sparked widespread protests and debates across the country, as some argued that the reservation policy could lead to reverse discrimination and undermine merit-based selection.

Overall, B.P. Mandal played a crucial role as the head of the Second Backward Classes Commission in identifying and recommending measures to uplift the socially and educationally backward classes in India. His leadership and the commission's report paved the way for the implementation of reservation policies that aimed to address historical inequalities and promote social justice.