AMONGST WOMEN By John McGahern Viking. 184 pp. $17.95

THE GREAT count got it wrong in his second greatest book when he said, "All happy families are alike, but an unhappy family is unhappy after its own fashion." The problem with Tolstoy's line is that there is no such thing as a family that is all one thing or all the other: In any family, as in any life, there are good days and bad days, and -- as the modern novel in its better incarnations has demonstrated -- no two families are alike. The dynamic of the family group is by far the most prevalent theme in too many of the world's stories to list, going all the way back to the Greeks (Sophocles's great play is a domestic tragedy, after all). And so even if one feels a certain itchiness, as I confess I did, opening a novel that announces itself to be about that honorable subject, one is quickly engaged, if the book is any good, in all the various lines of tension, the many places where the members of the fictional family miss each other.

At the center of John McGahern's fifth novel is Michael Moran Sr., a former soldier in the war for Irish independence -- an eccentric, religious, bitter man of protean moods and capricious shifts of demeanor, who, as such people so often are, is held in a kind of suspicious awe by others. He's a man in the middle of a long, losing argument with life, who happens also to be the tyrannical head of a large family of three daughters and two sons.

One son, Luke, is permanently estranged, living away from the family home. The other, Michael, is coming into manhood, and beginning to clash with his father's impossible expectations. The three daughters, Maggie, Sheila and Mona, somehow manage to get through the days in their father's house. They humor him, cajole and plead and -- very tentatively -- remonstrate with him; but more than anything they are interested in maintaining the peace, which means predicting the next mood, heading off the next tirade, melting back into the shadows of the upstairs rooms to be out of the way of trouble.

When Moran remarries, the stepmother, Rose, notices "that whenever Moran entered the room silence and deadness would fall" on the girls. "And if he was eating alone or working in the room . . . they always tried to slip away. If they had to stay they moved about the place like shadows. Only when they dropped or rattled something, the startled way they would look towards Moran, did the nervous tension of what it took to glide about so silently show."

Rose tries to soften his edges, and brings her ability to love into the equation, but nothing really softens Moran, and as the story unfolds of his decline into weakness and apathy, we come to see how the children have learned to depend on the strength -- ill-used and cruel as it has so often been -- of their patriarch. Somehow, even in his casual brutality -- and it is often enough psychological rather than physical -- he forms the lines that keep them together: the need and the fear, the love, the uncertainty and the pleasure, too.

For Moran is shown to be capable of moments of real thoughtfulness, even tenderness; and one feels for his inability to let go of his pride, to admit that the central fact of his life is that his strong will has been brooked by his oldest son, Luke, that his effect on Luke's life has been nullified by the boy's own willingness to accept an end to the ties of the family. Even so, the enormity of his habitual use of humiliation and innuendo, his sense of his power over the others in his house, and his willingness to use it to his own ends, make him a truly grotesque creation: a character of great evil, existing in a setting so normal as to open the vein of our richest horror.

The love we find in this family is that of the women -- especially of the stepmother, Rose, who bears the brunt of Moran's abuse without losing her pride or her sense of dignity. She causes him to curb his more destructive impulses, by her simple refusal -- her professed inability -- to remain in the house if she is not wanted. "I was told I was no use in the house. I couldn't go on living in a place where I was no use," she says at one point, after Moran has cruelly insulted her. "I'll have to go back to Glasgow and take up my life there again . . . I love you dearly and I love the house but I couldn't live here if I am not wanted."

Amongst Women is a disturbing novel, a story told simply, without flourishes or fanfares, of a single household which is at the same time a refuge and a tyranny; yet in the complexity of that fact, John McGahern finds, somehow, a source of light. Richard Bausch's latest book is "The Fireman's Wife and Other Stories."