1: Publishers don't like doing publicity for other publishers' writers (but they do like poaching each others' more successful ones).
2: The book trade (bookshops, wholesalers, book-page editors [when they existed] ...) were unhappy selling / stocking / reviewing a given writer more often than once a year, (but they'd turn a blind eye if each "writer" had a different nom de plume, pen name ... moniker ...).
3: I enjoyed writing these historical sagas and could manage two-per-year (three in 1982) so I played along.
It didn't always go smoothly.
Malcolm Macdonald wrote historical sagas set anywhere between 1800 and the 1930s.
became his American publisher. Then came ...
who invented Malcolm Ross to publish The Dukes in America while Knopf was still quite happily publishing Macdonalds. But Knopf took mighty exception to this dreadful treachery and swore the name of Malcolm Macdonald would never-ever again pass their lips.
became Macdonald's new publisher in America. But Ross's English publisher
commissioned a further 13 (lucky-for-some) sagas, all set in Victorian Cornwall. St Martin's published them all in America under the Macdonald name.
The early paperback editions of Malcolm Ross were published in England by a new British kid on the block named
(who later bought Hodder to become Hodder-Headline). On a Far Wild Shore was Headline's first-ever paperback.
The editors at Headline wanted a bit of the hardback action, too, and so asked me to pick an Irish name and write Irish sagas for them, also set in Victorian days. Thus was born...
M. R. O'Donnell whose four novels were published in America by St Martin's Press, again under the Macdonald name.
republished Malcolm Macdonald's four Stevenson saga novels under that name, and ...
... used that name to publish the Felix Breit Trilogy. Finally we have ...
Dorling Kindersley's first-ever book, The Origin of Johnny, was packaged in the UK for Cape and in the US for Knopf bearing my full surname:
M. J. Ross-Macdonald
Glad you asked?
[Maybe it helps to know that the full name on my passport is Malcolm Ross-Macdonald ? There's a story behind that, too.]