Her Canopus in Argos: Archives series was seen as a repudiation of the great naturalistic/realist work she had done up to that point. It was. She decided to become a realist in a new genre that she was about to invent. She was not going to be a captive of her own success.
Good for her.
There were inklings of change earlier with Briefing for a Descent into Hell which she characterized as "inner space fiction." Her five space fictions were just too much for the establishment to bear. Lessing had first dared to write about women in ways that had not been allowed, and then having done so with such brilliance, she had the temerity not to continue in this vein and change styles and genres again (which she continues to do this to this day).
Good for her.
The Canopus series is difficult since she was trying to write from a point of view never encountered in fiction before. Here is the complete title of the first book:
Re: Colonised Planet 5 Shikasta Personal, Psychological, Historical Documents Relating to
visit of Johor (George Sherban) Emissary (Grade 9) 87th of the Period of the Last Days
She was creating fiction out of documents of a non-human people and demanding of her readers the courage and hope to follow her into this new terrain. The first volume is difficult since she was creating a new voice and sending science fiction (all fiction actually) off in a unique direction. The voice became more assured with time and the fifth volume, The Sentimental Agents, is a masterpiece.
Once you give yourself over to her beautiful, annoying, challenging texts, you realize that you are in the hands of one of the most optimistic of all writers. She believes in the power of writing (and art in general) to change things for the better. I don't know how often emissaries from the Swedish Academy are sent to tell a writer that they are not ever going to win the prize, but the fact that the Academy thought it necessary to do so in the 1970's demonstrates how unnerving Lessing's work can be.
Her fierce, passionate writings are mirrored by the fierce and passionate responses her work evokes -- both pro and con. But Lessing has remained true to her commitment to write and and write well, and her books still divide the critical establishment.
Good for her.
Brian