radio serial (Slipback), stories slated for the "missing season" but never produced due to the 18-month hiatus in 1985-1986 (The Nightmare Fair, The Ultimate Evil and Mission to Magnus), the spinoff K-9 And Company, and even a 1976 children's story record (The Pescatons), which has the distinction of being the final Doctor Who book published under the Target imprint. (The Target logo was retained for later reprints and intermittent new titles up to 1994 and was by this time used exclusively for Doctor Who.) Most of these novelisations contained minimal amounts of original material and were (usually) adapted closely from the shooting scripts, with the intent of the books being souvenirs of previously aired shows in the pre-VCR era; the decision by the BBC to delete many episodes from the Hartnell, Troughton, and Pertwee eras resulted in many of these books becoming the only way for these "lost" adventures to be experienced prior to the release of soundtracks for those episodes and/or recovery of lost episodes (the Pertwee era, in particular, has been rendered intact since the early 1990s, and several Hartnell and Troughton stories are once again complete). Although novelisations became more elaborate in later years, the early books usually followed a set formula and were for a time restricted to a maximum page length as they were considered children's literature. Not all Target novelisations faithfully followed the scripts. John Lucarotti's The Massacre (1987) completely changed the plot of the source serial, The Massacre of St Bartholomew's Eve. Some guide books (notably 1999's A Critical Guide to Doctor Who on Television by Kenneth Muir) describe the plot of the novel rather than the original serial due to the fact the original serial is one of the many that were lost. Also, when Target launched the novelisation line, there was no inkling that ultimately more than 150 of the show's storylines would be adapted; as a result, there are numerous continuity gaps between early Target books and the scripts and/or later published novelisations; one example is Doctor Who and the Doomsday Weapon (based upon Colony in Space) which as written depicts Jo Grant's first adventure with the Doctor, even though the television series introduced her several serials earlier in Terror of the Autons (which was novelised at a later date and ignored the discrepancy). Authors sometimes added epilogues to their novelisations which were at odds with other material: The Curse