Publisher:Sidgwick & Jackson

Sidgwick & Jackson was originally established in 1908 and was acquired by Macmillan in the 1980s. Now an imprint of Pan Macmillan.

Wikipedia entry

Common ISBN prefix - 0-283.

Notable here for a lot of Anthologies - the "SF Specials" mainly, but single Author collections in earlier days. Mainly a hardcover publisher, but did do some paperbacks, or was sometimes credited as co-responsible on NEL paperbacks.