Prolific American inventor (1873-1961) often referred to as 'the father of radio' for his pioneering work in wireless telegraphy. Two items signed by de Forest: a matte-finish 3.75 x 4.5 portrait of the inventor, signed and inscribed in fountain pen; and a Lake Shore National Bank check, 6.25 x 2.75, filled out and signed by de Forest, payable to Pure Oil Service Station for $1.30, October 6, 1948. In overall fine condition.