CONRAD AIKEN'S new book is a terrifying psychological study of Jasper Ammen, an egocentric, ruthless character, who plans to commit murder simply to expand his great self-satisfaction. Ammen has heard somewhere the name "King Coffin." His desire is to fuse himself with that symbol, to become the awful, mystic figure of King Coffin himself.

He occupies himself with the search for a victime, most preferably someone ordinary, commonplace, average, whom he can observe and follow for a sufficiently soul-filling time before he strikes the blow. Up to a certain point "King Coffin's" plans go well; he has lured his prey here and there; he has him at his absolute mercy. Then a swift change of events alters the whole aspect of the situation. Ammen begins to regain his sanity.

Aiken's central character is a decidedly different creation. He looks at himself in the mirror, admiring his lean, dark face, his masterful eyes. He sneaks into his friends' dwellings when they are not there and furtively reads diaries and personal mail. He leans out of the window of his apartment on Plympton Street and wants to kill an editor of the Crimson who is unobtrusively sunning himself on the roof. He artfully spins webs of deception around his acquaintances, lets them in part-way on his secret, laughs at their wholly average protestations.

Jasper Ammen is a singularly unpleasant person to read about. Some will find it hard to sympathize with him, others will find delight in a sublimation of their "Superman" tendencies. To anyone Conrad Aiken's portrait is a fearfully real one.

From a purely external point of view we wonder how much the background of this novel, which is Cambridge and Boston and especially the region of Harvard Square, will mean to the outside. The story is full of touches and names, many of them literal (King Coffin has the residents of the Plympton Street apartment all agog. Aiken lived there until last year), which accentuate the horror of the story by their very familiarity.

Courad Aiken possess a tremendous ability to trace and realize the aberrations and fixations of the human mental mechanism which he displays impressively in King Coffin. The whole study is brilliantly worked out, convincingly set down. If is a document that should endure