Baldev Singh was born at Dumna in Ambala district in 1902, ran the family steel business, and entered Punjab politics in the 1930s.
He was the Sikh representative in the negotiations of 1946 and 1947, was a member of the interim government, and became independent India's first Defence Minister.
He held that office through the partition of the army, the movement of units and stores between two dominions in a matter of weeks, and the 1947 to 1948 war in Kashmir.
The division of the Indian Army in 1947, splitting regiments, equipment, records and men by religion under a fixed deadline while the country burned, is one of the least examined administrative operations of the period, and it was coordinated by Field Marshal Auchinleck's Supreme Commander's Headquarters under the Joint Defence Council, with Baldev Singh as India's Defence Minister.
He signed the Sikh acceptance of the Constituent Assembly's arrangements, a decision argued about in Punjab ever since.
He died in 1961. A road in Delhi carries his name and there is no biography of him.
He was Development Minister in the Khizar Hyat Tiwana coalition in Punjab before he went to Delhi, which is how a steel manufacturer from Ambala district came to be the man the Panthic board sent to sit with the Cabinet Mission.
The Sikh position in those negotiations was that the community should not be divided. The boundary drawn divided it precisely, leaving the Guru period sites and half the Majha on the other side.
He was out of the Cabinet by 1952 and lost his seat afterward. Of the men who signed for the three communities in 1947 he is the one about whom the least has been written, and the arguments about what he agreed to are conducted without anybody having gone through his papers.