Frankham-Allen served as the head writer and range editor, with Shaun Russell, Hayley Cox, Will Rees, Lauren Thomas and Keren Williams serving as co-editors on various books.
The stories initially bridged the gap between The Web of Fear and The Invasion, but with The Laughing Gnome series (which debuted in August 2018), as well as the rest of Phase Two, the range began to take place throughout Doctor Who's history. They were not licensed by the BBC but by the Haisman Literary Estate, the copyright holders for the character. They included various elements of other Doctor Who stories, by agreement/license of the original authors, such as Terrance Dicks, who wrote Horror of Fang Rock, and Gary Russell, who created the Vault in The Scales of Injustice.
The series particularly delved deeper into the history and character of Alistair Lethbridge-Stewart, creating a whole family for him not previously seen on television. Family members included; Mary Gore, his mother, James Lethbridge-Stewart, his older brother who died in 1938, and Gordon Lethbridge-Stewart, his father, a commander in the RAF who was declared Missing In Action at the end of World War II. It also debuted his children and grandchildren with Doris Lethbridge-Stewart, the Wilsons (son, Albert, daughter-in-law Tamara, and grandchildren Conall, Nick and Lucy). Lucy would later head her own series of spin-off novels, with guest appearances from various members of her family.
Along the way the series also delved into the Brigadier's ancestors and extended family, including cousins, uncle, and grandparents. Most notably in the short story anthology, Lineage.
The series also developed an extended family for Anne Travers and her father, Professor Travers. These included; Alun Travers, Anne's brother. Lyndon Travers, Anne's grandfather and Professor Travers' father. Margaret Travers, Anne's mother and Traver's wife, and Travers' twin, Vincent and his children. Ben Travers, from Horror of Fang Rock, was revealed to be the uncle of Professor Travers.
In addition to the novels, which initially followed an ongoing narrative, the short stories occasionally dipped into different periods of Lethbridge-Stewart's past and future. For instance, Ashes of the Inferno was set directly after the TV story, Inferno, and The Lock-In was set around the time of his death, with Of the Future exploring the divide between the Brigadier and his daughter, Kate, and the birth of his grandson, Gordy. The Enfolded Time brought focus on the UNIT dating controversy and could be said to finally solve the longstanding dating issues once and for all, though the regularity with which spin-off media attempts to "fix" the controversy makes it one of many.
From late 2018, with The Laughing Gnome series of books, the range moved from the ongoing narrative that featured in the first sixteen novels, and began to dip into various periods of Lethbridge-Stewart's past, present and future. This would be the beginning of Phase Two, and The Laughing Gnome would later be followed on with Bloodlines, as well as several Special Editions of previous novels and anthologies, including previously unpublished material.
It was announced that a sequel to the 1995 home-video release Downtime was in development, in conjunction with Reeltime Pictures.
Many short stories were released digitally to tie into Lethbridge-Stewart novel releases; these were later collected alongside original stories in a number of Lethbridge-Stewart anthologies.
