Making films about World War II is like concocting compounds in organic chemistry. There are roughly half a dozen entertaining ways to kill a soldier, nine or ten basic acts of Nazi inhumanity, perhaps fifteen kinds of heroism in combat, and at least a hundred bits of cliched battle dialogue. To put together a new movie, the writer and director have only to choose several ingredients from each grouping. Allowing for duplications, countless combinations can be made. Very few are worth the trouble.

Originality comes especially dear in retelling wars that are neither small nor remote enough to make individual actions seem romantic. Ghastly statistics simply smother any kind of gaudy derring-do. For a battle narrative set within the slaughter of thirty million human beings, the courage and suffering of ordinary people are the only legitimate themes.

The Four Days of Naples attacks these themes without pretense, and the result is an unusually appealing permutation of standard war-story elements. Permutation is the appropriate word here, because this Italian film has no new novelties to offer. It gives a straight forward account of civilian resistance to a German occupation after Badoglio's surrender in September, 1943. The citizens of Naples hail the armistice, then discover that Hitler intends to defend Italy and treat his former allies as a conquered people. When the Wehrmacht starts rounding up men for labor crews in Germany, Naples rebells. Four days later the harassed Germans release hostages and abandon the city.

Honesty and balance distinguish The Four Days of Naples from dozens of mediocre predecessors with similar plots. The film does not pretend that a latter-day Spartacus rallied the Italians around an American flag, or that a massed charge of Neapolitan housewives armed with brooms broke the nerve of veteran troops. The resistance forces use modern weapons, look scared, and get shot in large numbers. They will rise up spontaneously and fight without organization. The struggle is so makeshift that indignant residents often ask the street-fighters to take their battles elsewhere. Only the occasional reappearance of the same characters and places gives continuity to a brisk sequence of skirmishes and personal episodes.

The Four Days of Naples evokes sympathy for its Italion protagonists with a minimum of melodrama. It even dares to intersperse this subject with frequent snatches of ironic comedy--a gentleman, for instance, running through the streets in pajamas crying, "Rejoice, solders! We lost the War!" A cast left anonymous in tribute to the real Naples performs superbly, especially, in its use of animated facial gesture. One man being led away for the work crews wrinkles his features into a soulful stare that would have made Chaplin envious. Photography and timing art both managed with artistic sensitiveness.

The film does have its silly moments. There is a man eager to see a newborn son who mutters a last message in a companion's arms. There is also a captive German officer who wistfully admits that he misses his frau and kinder. But despite a liberal complement of platitudes, The Four Days of Naples never really becomes embarrassing. And it does invent many lively and believable ways to thwart Germans--probably the critical test of a movie that never even presumes to squeeze clumsy lessons out of the bestiality of war.