This is the serious bit. Those who know me know that I'm a bit of a space cadet, and am likely, given the opportunity, to expound at length on aspects of written Science Fiction in exhausting and terrifying detail. Luckily for them, those who know me are now adept at finding excuses to leave at this point, or else they start talking about pies, knowing how easily I can be distracted by such things.
However, there are people who do not know me, and who share my interest in SF. Conversely, there may be people who think that SF begins and ends with Star Trek, and may be pleasantly surprised (or not) to discover otherwise. Either way, I hope at least one person will take the time to attempt to read just one of the books mentioned here. Then my work will be done.
Here, I will be posting my thoughts on excellent examples of the genre. If a book is discussed here, it is recommended that you read it. You may not like it, but at least it means you don't have to talk to me about pies.

Patternmaster - Octavia E Butler (1976)

Octavia Butler is a black American writer who, in her later novels, manages to successfully combine feminism, Black issues and SF into some brilliant work.
'Patternmaster' is her first novel, and though it doesn't have the power and depth of her later work it's an excellent exercise in creating a realistic society in which these post-humans have evolved advanced paranormal powers.
Homo Superior is most often depicted as a powerful but benign species, above the petty squabbling of us mere sapiens, and mostly used as a device with which to hold a mirror to ourselves. Butler's Patternists have no advanced moral sensibilities to accompany their formidable powers and are locked not only into the 'Pattern' of linked psychic energy which binds them but also a hierarchical slave culture based on mental power.
The system is brutal, controlled from the summit by the dying Rayal while his children battle murderously to succeed him.
The novel is set in some unspecified future and suffers in this respect from no real contact with our present. Butler's subsequent novels, including the far superior prequels, 'Wild Seed' and 'Mind of My Mind' are set either in the past or in contemporary USA, and go far deeper into examining the dynamics of power between individuals.
The issue of slavery recurs again and again in Butler's work, as it does here when Teray - one of two powerful candidates for the position of Patternmaster - is forced into a choice between accepting a benign form of slavery to his brother or losing his wife. Understandably perhaps, the richest characterisations are those of the women, who are for the most part frustrated and exasperated by the patriarchal system which has evolved within the constraints of The Pattern, but nonetheless attempt to find ways to use the system to their advantage.
It's a short, deceptively simple novel, but one which still manages to explore the human capacity for exploiting its own species, a theme which is later more extensively developed in 'Wild Seed' and indeed, in most of her work since.

Linked novels: 'Wild Seed' (1980) 'Mind of My Mind' (1978) and 'Clays' Ark'.