Frederick Valentine "Derick" Atkinson (25 January 1916 – 13 November 2002) was a British mathematician, formerly of the University of Toronto, Canada, where he spent most of his career.
Auto-didactic when it came to languages, he taught himself and became fluent in Latin, Ancient Greek, Urdu, German, Hungarian, and Russian with some proficiency in Spanish, Italian, and French.
His dissertation at Oxford in 1939 established, among other such results, asymptotic formulae for the average value of the square of the Riemann zeta function on the critical line.
His first academic appointment was at Magdalen College, Oxford, in 1939–1940, followed by a commission (1940) in the Government Code and Cypher School at Bletchley Park.
He is best remembered for his classic text "Discrete and Continuous Boundary Problems" (1964), and his seminal contributions to differential equations as outlined in the margin.