Beware the Eighth of August : A DARKER MAGIC<i> by Michael Bedard (Atheneum: $13.95; 183 pp.; ages 10-14) </i>

The occult becomes more chilling when it is dramatized against our day-to-day lives, when we are lulled into an unsuspecting vulnerability before a hand from another world suddenly reaches out to touch us. Michael Bedard skillfully uses this technique, setting the scene in a small, quiet town and pitting three gentle, naive individuals against a demon with destructive strength.

While most books for children in this age group are written from a single viewpoint, Bedard bends the rules in order to tell his story through the minds of independent Emily, whose major problem is her spoiled and noisy young brother; Emily’s classmate, Craig, who desperately wishes for a close friend; and their teacher, Miss Potts, who, while cleaning her classroom at the end of the school term, discovers an old handbill for Professor Mephisto’s “Evening of Magic and Mystery,” to be presented for children only, on Saturday, August 8, in the waiting room of the town’s depot.

The handbill is old and brittle and identical to one she received many years ago, when she was a child, and the town’s depot has long been closed. Miss Potts well remembers begging and pleading with her mother to let her attend the magic show, and she is badly frightened as she recalls the strange, compelling magician and the terrifying climax of his program.

August the eighth. Again, this year it falls on a Saturday. Does the handbill refer to this date? Working with a fearful urgency, Miss Potts tries to discover how the handbill got into the desk of one of her students. She searches her memory and comes up with six students who sat at that desk at one time or another during the term and begins to telephone them. One of these students is Emily, who had found the handbill on her desk.

Miss Potts tells Emily about the magic show she had attended and about her friend, Freddie--a volunteer from the audience--whom the magician had beheaded. Of course, it had been only a magic trick, but from that moment on, a peculiar red welt had circled Freddie’s neck, and soon afterward, he had a terrible fall, dying of a broken neck. Miss Potts knows this magic show must not be allowed to take place again, and it’s up to her and to Emily to stop it.

Unaware of the dangers of the approaching day, Craig keeps a promise he made to a new student in his class, Scott Renshaw, a boy who had befriended him against the school’s bullies. Craig visits Scott’s home; becomes both frightened and fascinated by Scott, his attitude of dark mystery, and his skill at magic, and finds himself stealing a strange little book of magic from Scott’s room.

Tension increases as Craig becomes enmeshed in the web Scott skillfully builds for his intended victim, and both Emily and Miss Potts fight against Mephisto’s powers. Occasionally in the telling of his story, Bedard suddenly flashes back to other horrific magic shows, and it is one of these--in which a little girl from the town is not only made to disappear, but disappear forever--that gives Emily and Miss Potts the proof they need and the direction they must take to keep this evil from taking place again.

After Emily manages to thwart the magician and save Craig, Miss Potts warns her that there will be other years in which August eighth falls on a Saturday, and she must be prepared. The magician will undoubtedly return in another guise.

With all the emphasis on a specific date throughout the story and with the splendid tension leading to a horrific climax, the last chapter, which concerns Craig, seems unnecessary. It refutes what Miss Potts has told Emily and leaves readers wondering why.

This is a book that is well written but, because of its broad leaps from the mind of one character to another and from the present to the past and back again, will appeal more to older readers than to those for whom it’s intended.