The Analytic S-Matrix - Eden, R. J., Landshoff, P. V., Olive, D. I., Polkinghorne, J. C.

Considerable interest has centred on attempts to formulate interactions between elementary particles in terms of the S-Matrix, an operator which connects the input and output of a scattering experiment without seeking to give a localized description of the intervening events. Originally published in hardback in 1966.