From the introduction of his 1977 book Picked-up Pieces, John Updike offers six rules on good reviewing (which, unfortunately assume the author is male):
My rules, drawn up inwardly when l embarked on this craft, and shaped intaglio- fashion by youthful traumas at the receiving end of critical opinion, were and are:
- Try to understand what the author wished to do, and do not blame him for not achieving what he did not attempt.
- Give him enough direct quotation–at least one extended passage–of the book’s prose so the review’s reader can form his own impression, can get his own taste.
- Confirm your description of the book with quotation from the book, if only phrase-long, rather than proceeding by fuzzy precis.
- Go easy on plot summary, and do not give away the ending. (How astounded and indignant was I, when innocent, to find reviewers blabbing, and with the sublime inaccuracy of drunken lords reporting on a peasants’ revolt, all the turns of my suspenseful and surpriseful narrative! Most ironically, the only readers who approach a book as the author intends, unpolluted by pre-knowledge of the plot, are the detested reviewers themselves. And then, years later, the blessed fool who picks the volume at random from a library shelf.)
- If the book is judged deficient, cite a successful example along the same lines, from the author’s ouevre or elsewhere. Try to understand the failure. Sure it’s his and not yours?
Whether or not it’s a good or bad trend (and being an author I’m bound to mention this point), I suspect too few reviewers of science fiction and fantasy fiction really seem to put much effort into point 1. Perhaps that’s because genre critics are fascinated with taxonomy and heritage, and end up trying to compare the book to others, rather than examining it in isolation. Maybe that’s just the nature of genre, though.