Publisher:Michael Joseph

Presumably founded around 1936, as "At the Sign of the Mermaid, Fifty Years of Michael Joseph" came out in 1986.

In 1985 Thomson Books sold Michael Joseph and some other imprints to Pearson-controlled Penguin. The imprint is still in use and you can search for Michael Joseph books at the Penguin UK website. However, it seems to rarely publish SF any more.

Most books seem to be Hardcover, now along with hard-cover-sized trade paperback versions. No sightings of a normal paperback - these would be covered by another imprint. The usual ISBN prefix is 07181. OCLC usually lists the publisher as "London: Joseph".