Short answers, pulled from the story.
Hodder & Stoughton became a distinct publishing house in 1868. This formal creation occurred when two partners retired from the company and Thomas Wilberforce Stoughton joined the partnership.
Leslie Charteris created The Saint adventure novel series which the company acquired exclusive British hardback rights for in 1928. They published all fifty UK first editions of the series until 1983.
Five on a Treasure Island launched the Famous Five series in 1942. Ernest Roker managed the operation and persuaded author Enid Blyton to write about four children and a dog for the new imprint.
Thomas Keneally won the Booker Prize in 1982 with Schindler's Ark published by Sceptre. Keri Hulme received the same honor in 1985 for The Bone People acquired from their New Zealand office.
Hachette Livre purchased the entire group two years after W H Smith acquired Hodder Headline in 1999. This acquisition occurred in 2001 when they took over Time Warner Book Group making them the UK's lead publisher.