John Sculley, 54, is the hero-turned-goat of Apple Computer (he built it up, ran it down) who stunned the industry last fall when he took a job as CEO of Spectrum Information Technologies, a little company with as dubious a reputation as some of its more famous Long Island neighbors like Joey B. and Amy. Sculley believed he could turn Spectrum into a major player in wireless technology, and he signed on for a $1 million salary and a boatload of stock options.

Now Sculley has quit Spectrum and sued its president, Peter Caserta. He charges that Caserta lied about Spectrum’s finances and about a Securities and Exchange fraud investigation because he thought hiring a big name would boost the stock (it did) and let Caserta make big money selling his shares (he did), Last week Spectrum countersued, saying it hid nothing. Sculley wanted to get out of his contract, Spectrum charges, and spent weeks plotting an escape at Spectrum’s expense.

If this case of “he said, he said” were set in a skating rink, the motives might be obvious. But stories set inside corporations often look somewhat opaque because of the persistent myth that the players are rational men, making rational decisions (buy a company, launch a product) based on the hard truths of the market. in fact, the tabloid motif – dominated by earthier human emotions such as fear and denial – is just as relevant.

Until recently Sculley was seen as one of those sure-thing CEOs, on the short list for any big urgent job. He came to Apple from a successful career at PepsiCo and built the faltering computer start-up into an $8 billion standard-bearer. But a few years ago Apple began to stumble, and Sculley got the blame, particularly for problems with his own pet product, the Newton “digital assistant.” By last summer the board was reportedly pushing him to leave.

Then came a fateful phone call. An old Pepsi acquaintance said she wanted Sculley to meet Caserta, a patient in the chiropractor’s office where she now worked. Until then Sculley knew of Spectrum only what had been in the press: a string of lawsuits, an earlier SEC investigation and a delisting by the stock exchange. Last spring Spectrum’s stock had soared when it announced a lucrative deal with AT&T, then plunged after AT&T said Spectrum had exaggerated.

But Sculley found Caserta’s technology seductive. When he invited Caserta home, the Spectrum president showed him how his product could work miracles with the maligned Newton. Sculley was hooked. He stopped long enough to have lawyers study Spectrum’s patents. But he didn’t so much as read a lawsuit about the AT&T caper or review Spectrum’s books.

Once inside, Sculley began to clean house, easing out some executives and hiring new accountants. Friction soon developed between Caserta and Sculley, who were an awkward match, says one Spectrum investor, of “street smarts and the Greenwich [Conn.] crowd.” But Sculley claims he knew nothing of the SEC investigation until January, or of Spectrum’s financial problems until February. On Feb. 7 Spectrum revealed that a $1.1 million profit reported earlier was a $7 million loss, and Sculley resigned.

Last week Sculley watchers were stuck with two unsatisfying scenarios: either he knew more than he admits, or he should have. But maybe Sculley, on the rebound from Apple, didn’t want to know. According to associates, he was at once naive and greedy. When Caserta “looked him in the eye” and said he was clean, says one associate, Sculley believed him. Then there were the stock options, valued at as much as $72 million. Sculley could have gotten a hefty package – but probably not that good – at a company such as IBM or Kodak. But he was determined to build up a small company, not try to rescue a big one. And acquaintances say he wanted the income necessary to live in the lavish manner to which his family had grown accustomed.

Sculley may find some vindication, especially if the SEC, which has subpoenaed Spectrum documents, brings indictments. Meanwhile, industry sources say Sculley will surely find gainful employment. But his image will be different. A little less businessman, perhaps; a little more human.