Eneas Sweetland (E. S.) Dallas (1828–1879) was a journalist who worked for The Times among other publications and whose interest in psychology and love of poetry led to his writing the two-volume – though he originally intended four – The Gay Science, published in 1866. The work takes its title from an expression used by Provençal troubadours to describe the art of composing poetry, and the volumes are concerned with the unclear and often shifting boundaries between art and science and whether they can be reconciled.