A Fascinating Study of History’s ‘Wild Child’ : LOST PRINCE: The Unsolved Mystery of Kaspar Hauser by Jeffrey Moussaieff Masson; Free Press $23, 254 pages

Although there is voluminous literature in German on the “wild child” Kaspar Hauser, those familiar with his story in this country are likely to know it either through Werner Herzog’s beautiful 1975 film “Every Man for Himself and God Against All” or Jacob Wassermann’s sympathetic 1908 novel, “Kaspar Hauser.”

The bare bones of the story: On May 26, 1828, Hauser, a young man of 16 or 17, was found standing mute and motionless in the streets of Nuremberg, clutching a letter addressed to the “Captain of the Fourth Squadron of the Sixth Regiment of Light Horses.” He was discovered to be almost incapable of walking and, aside from a few crude memorized phrases, devoid of the faculty of speech.

As he was examined, often thoughtlessly teased and occasionally educated over the following months, his remarkable innocence and unique intelligence galvanized the interest of many, not only locally but throughout Europe, and strange facts and assertions began to emerge. It was an era when theorists of language, of “natural man” and of education were only too ready to latch onto “wild children” to prove their varied hypotheses.

Those who first attempted to elicit his history ascertained that Hauser had been kept in a dark room, sequestered from human contact and possibly drugged, for as long as he could remember. Bread and water, replenished while he slept, were his sole sustenance. His only companions were two wooden horses and a toy dog. Such was his existence for at least a dozen years.

Then one day “the man with whom he had always been” came, stuffed his feet into some ill-fitting boots, tried to teach him to walk on his malformed legs and half-carried him to Nuremberg.

Hauser had no sense of time, so he had no idea how long he had been imprisoned (indeed, had no way of understanding it as imprisonment) or how long the journey to Nuremberg had taken. One of the first talents he showed in Nuremberg was drawing, which he pursued zealously. One imagines that it was an important way of organizing the world since he had trouble understanding the difference between animate and inanimate things.

As Hauser’s “case” became known throughout Europe, persistent stories--more than rumors--arose that he was the heir to the throne of Baden, the son of Napoleon’s adopted daughter Stephanie de Beauharnais, whose four sons had mysteriously died shortly after childbirth.

A mysterious death was eventually to be his lot in any case. In October 1829, a man dressed in black came to the outhouse where Hauser was and tried to cut his throat. He was only wounded, but in his delirium he shouted, “You kill me before I understand what life is. You must tell me why you locked me up!” Three years later he was lured to a park by a man who stabbed him in the chest. He died shortly afterward and the crime was never solved.

“Lost Prince” is a fascinating but oddly unfocused book. It begins with a 70-page introduction, followed by Masson’s translation of one of the important eyewitness accounts, by a lawyer who took a great interest in the child.

In appendixes, the book includes Masson’s story of finding a “new Kaspar Hauser manuscript” by one of his early teachers, though he gives no excerpts from it, and a translation of Hauser’s fascinating attempt at an autobiography,

Masson’s brief take on the Hauser case in terms of modern child abuse will appeal to some; to others it will seem irrelevant. No matter: This roving intellect has once again come up with a treasure trove, if unfortunately in the form of a grab bag.