Christos Achillios was born on Cyprus in 1947, moving to Britain in 1960. He studied art at Hornsey College of Art. His first book cover art was for Tandem Books - subjects ranging from Westerns to Science Fiction and Fantasy (such as the Pellucidar books of Edgar Rice Burroughs).
The Target imprint began in earnest in 1972, when they bought the paperback rights to three previously published Doctor Who novelisations - Doctor Who in an Exciting Adventure with the Daleks, Doctor Who and the Zarbi and Doctor Who and the Crusaders.
Achilleos was commissioned to provide new covers for these and we saw his trademark style for the first time. This featured a B&W image of the Doctor, in a colourful setting, but against a stark white background. The background would be made more interesting with some special effects, such as planets and starscapes or strange clouds. The Cave Monsters was enlivened with a volcanic landscape.
The first three books were published in 1973, and Target had agreed with the BBC for the novelisation of more stories. Initially these concentrated on the current Doctor - Jon Pertwee. Achilleos' personal favourite Doctor to paint was Patrick Troughton, because of his interesting lined face.
Later books dispensed with the white background. After a time, Achilleos grew dissatisfied doing the covers, the amount of work far outweighing the money he was receiving. He painted the covers for the first 12 books, then stood down for the next 4 (Peter Brooke took over). He then did the next 16 consecutive covers, after which he finally moved on to other projects. As well as the story titles, Achilleos also provided the art for a number of other publications - such as the two Target Monster Books. He was not happy to discover that the artwork for the first of these was being adapted for advertising without his knowledge or consent. He was particularly angry when the cover art of the Second Doctor Who Monster Book was used to promote Time Life's purchase and broadcast of the run of Tom Baker stories in the USA.
In recent years a number of artists attempted to create book covers for Nu-Who stories in Achilleos' style - so it only made sense for him to return and create some himself.
In May 2016 I had the pleasure of seeing some of his original cover art at London's Cartoon Museum, where it hung alongside the work of other Target artists.
Like all Target cover artists of the time, Achilleos was rather dependent on publicity images supplied from the BBC. His likenesses of the Doctors were superb, and you can often spot the photographs from which he took them. Other characters were sometimes taken from photographs as well. The Nestene octopoid on the the cover of Doctor Who and the Auton Invasion, however, came from an unrelated comic strip. For Doctor Who and the Zarbi, he provided some wonderful real ant images - but the BBC vetoed this, saying the Zarbi had to look like they were seen on screen. When it came to Daleks, he tended to use the ones taken from the TV Century 21 comic strip. For Doctor Who and the Dalek Invasion of Earth, he got the right Daleks, but used the movie spaceship and Roboman.
My personal favourite of his covers just happens to have the wrong thing on it - Doctor Who and the Cybermen is an adaptation of The Moonbase, but features a Cyberman from The Invasion. (Still, another artist - Jeff Cummins - made exactly the same mistake for Doctor Who and the Tomb of the Cybermen).
A lot has been said about the importance of the Target books in the pre-video days, as the only means of reliving these stories. There was a general dearth of imagery from the series as well, unless you happened to have the Radio Times 10th Anniversary Special or those aforementioned Monster Books. Achilleos' covers gave us a visual reminder of those stories, so were treasured just as much as as the contents.