Hamilton folded the magazine in October 1957, because they needed cash to finance an investment in the UK rights to an American best-selling novel.

In 1950, science fiction (sf) magazines had been published successfully in North America for over twenty years, but little progress had been made in establishing British equivalents.

[3] Since 1939, Atlas, a British publisher, had been producing a reprint edition of Astounding Science Fiction, one of the most well-regarded American sf magazines.

Landsborough did his best to improve the quality of the science fiction he was publishing, and was allowed to offer £1 per 1,000 words for selected material.

On 1 January 1951, Hamilton published Mushroom Men from Mars, by Lee Stanton, which was a pseudonym for Richard Conroy.

With the next book, Roy Sheldon's Gold Men of Aureus, Landsborough changed the banner to read "Science Fiction Fortnightly No.

[5] In addition to the banner, a contents page (including a date and issue number), a letter column, an editorial, and an advertisement for subscriptions were inserted.

Landsborough was concerned about the workload, and also felt it would be difficult to find enough good material; Hamilton refused to increase the pay rate, which was not high enough to attract the best stories.

Hamilton also ran a science fiction paperback imprint, Panther Books, which would go on to become one of the leading British sf houses.

[4] Tubb had contributed a great deal of material to the magazine under various pseudonyms, often amounting to more than half of an issue's fiction, and he later recalled that Campbell's way of hiring him as editor was to say to him, "As you're practically writing it, you may as well edit it.

As a result, he found it difficult to keep standards up, often finding himself forced to write material under pseudonyms to fill an issue.

However, later that year, Hamilton made the decision to invest a substantial sum in the UK paperback rights of an American best-seller: it is not known for certain which book this was, but it is thought to have been Evan Hunter's The Blackboard Jungle.

Hamilton could no longer afford to have cash tied up in Authentic, and in the summer of 1957 Tubb was given two months to close down the magazine, printing stories that had already been paid for.

With issue 29, the full-length novel, Immortal's Playthings by William F. Temple, was accompanied by a short story, Ray Bradbury's "Welcome, Brothers!"

Issue 41, for example, ran Richard deMille's "The Phoenix Nest" as the lead story, with fewer than forty pages of text.

Finally, in issue 60 (August 1955), the word "feature" was removed from the contents page, and with it the last vestige of the origin of the magazine as a series of novels.

[4][5] Regulars in the magazine included Sydney J. Bounds, William F. Temple, Bryan Berry, and Ken Bulmer.

With issue 29 a layout using a yellow inverted "L" to frame the cover picture was introduced, and the page count was increased to 148.