During the original run of Space: 1999, the science-fiction series generated a number of media tie-ins, including novelisations, original novels, comic books and audio dramas. Due to the series' ongoing cult following, new tie-ins continue to be released to this day.
In the mid-1970s, a number of books were published by both American (Pocket Books) and British (Futura) publishers, consisting primarily of novelisations of Space: 1999 episodes. These releases, mainly paperback, were supplemented by 16-page photo sections (Year One and Two in the United States, Year Two only in the United Kingdom), which comprised black-and-white stills from the episodes. Original novels, without photo section, also formed a part of the series. Many of the books were also translated for release in overseas markets, such as Germany, Turkey and Japan.
Space: 1999 novels and novelisations were also written in other languages for specific markets, mainly Germany and Italy, where the series was highly popular.
In Italy, adaptations of all 24 Year One episodes and eight of the Year Two episodes were published in oversized hardback volumes. These books typically contained two episodes and nearly 100 colour photos each. Like the Michael Butterworth English-language editions, many of these books were adapted from early drafts of scripts, and events and details sometimes differ significantly from the episodes later aired.
In Germany, the Butterworth Year Two novels were translated into German, with one significant difference. The ending of "The Edge of the Infinite" was altered in order to set up events that would be continued in six original follow-on novels. To this day, these novels have never been translated into any other language.
The final novel, Der Stahlplanet is notable in that it concludes the Space: 1999 odyssey by having the Alphans teleport to Texas City, Earth via the neutrino transmission process introduced in "Journey to Where". These books are also unique in that they are the only media tie-in novels for an English-language series written specifically for a foreign market.
In 2002, Fanderson published a new edition of the novel Earthfall which corrected the typographic errors of the original publication and, with the permission of the author, separated the novel into its three component sections: Part One, "Breakaway" (set in September 1999); Part Two, "Colony Alpha" (January 2000); and Part Three, "Earthfall" (October 2018). Fanderson went on to publish a new original novel, Earthbound, written by E. C. Tubb, in 2003. This book contained an adaptation of "Earthbound", the one episode which was not included in the original novelisation run, as well as adaptations of two scripts of Year Two stories which retained the Year One format in which the scripts had originally been written: "The Exiles" and "The Face of Eden" (or "The Immunity Syndrome"). Also in 2002, Eagle One Media published a new edition of the novel Alien Seed with a new preface by Tubb. The same year, Powys Media launched a new series of officially licensed original novels and related works of non-fiction, and revised and expanded omnibus editions of previously issued novelisations for Year Two. All books are English-language releases, available directly from the companies' websites.