By day, the prosecution and the defense agree, Dr. Edward F. Jackson Jr. was an excellent and exemplary physician, respected by his peers in Columbus and known among his patients as caring, compassionate and unconcerned about whether they could pay their bills.

But by night--and both sides also agree on this--Jackson was a rapist, methodical in his stalking of single women, meticulous in planning his break-ins and in carrying out his attacks, which were brutal if the women acquiesced and extremely brutal if they resisted.

And he did it over and over again for nearly seven years.

"A plague of rapes on Columbus," chief prosecutor Edward Morgan told the jury in his opening statement.

"Gruesome and horrible acts . . . by a Dr. Jekyll and Mr. Hyde," chief defense attorney John W.E. Bowen added.

The two sides diverge on why, and that is the crux of Jackson's current trial, now in the second of what could be six weeks.

The trial was moved from Franklin County Common Pleas Court in Ohio's capital city 125 miles northeast to Summit County Common Pleas Court in Akron because of extensive news coverage of the case in Columbus, stemming, in part, from the freeing of an innocent man.

The same day that Jackson was indicted--last Sept. 22--a near look-alike, William Bernard Jackson, 30, was freed after spending five years in prison on a conviction for two rapes in which Edward Jackson is now charged. The two Jacksons are not related.

Edward Jackson, an internist, was born in Washington in 1944, and his parents moved to Columbus early in his childhood. He is 39, married and the father of two teen-age daughters. He is on trial on 60 charges, including 22 counts of rape, which occurred--according to a neatly kept list found in Jackson's car--from Nov. 26, 1978, until his arrest last Sept. 5.

Jackson has remained free on $300,000 bond. His medical privileges were revoked at two Columbus hospitals and he resigned from the board of one, but has continued to see patients in his private practice. A move by Ohio's state medical board to revoke his license failed in the courts.

Jackson's alleged victims were women 21 to 45 years old, black and white, secretaries, nurses, psychologists, lawyers, businesswomen--and one Roman Catholic nun. Others were unemployed. In three instances, Jackson is accused of breaking into apartments shared by two or three women and sexually assaulting all the occupants.

There also are 36 earlier charges, including 15 counts of rape, that are expected to be decided in a second trial because of a 1978 change in Ohio law governing the verdict his attorneys are seeking: not guilty by reason of insanity.

The defense admits that Jackson committed the 60 crimes in the current trial, but Bowen, 56, and his assistant, James Lewis, 35, contend that Jackson was legally insane when the crimes were committed and cannot be held criminally liable.

Bowen told the jury in his opening statement that Jackson has suffered for 25 years from a "compulsive, obsessive" mental disorder. He said that Jackson acted out the initial, occasional fantasies by being a Peeping Tom. But in 1974, his mind "literally inundated by fantasies," he was driven to "rape and bondage" to "fulfill a desire to control others by rendering them helpless," Bowen said.

To prove this, Bowen said, there will be testimony by "the very best experts in the country"--not "hired guns" but psychologists and a psychiatrist who have testified in other cases, more often for the prosecution than for the defense.

Bowen offered to accept the victims' written testimony and spare the 30 women who have agreed to testify against Jackson in court.

Morgan, 38, a 10-year specialist in trying rape cases, rejected the offer. In his opening statement, Morgan said that jurors should not discount the testimony of experts, but also should listen closely to the victims and give them justice. A state psychiatrist and three psychologists are expected to testify that Jackson was legally sane.

"Only the victims saw the defendant at the time he was claiming to be insane," Morgan said, adding: "The best way to understand what was going on inside his head is to look at what he did and what he said."

In Ohio, a person is judged legally insane if he cannot distinguish between right and wrong, or cannot refrain from doing wrong. Both sides say that Jackson knew he was doing wrong, but the defense contends that Jackson was unable to stop because of his mental disorder.

Before November, 1978, Ohio law required the prosecution to prove the defendant's sanity in such a case. Since then, it has required the defense to prove insanity. Because the charges against Jackson span the legal change, he is on trial under the recent law, and will be tried later in the crimes that occurred under the earlier law.

Guilty verdicts in either trial could result in consecutive prison terms amounting to several hundred years. If both trial juries find Jackson not guilty by reason of insanity, he would be sent to a mental institution until he is judged to be restored to reason.

With insanity the only real issue, Judge Frederick Williams, 57, allowed attorneys broad leeway in questioning and selecting the jury of six men and six women, with an unusually large number of alternates--four men and two women--because of the expected length of the trial.

According to prosecution accounts of the attacks, Jackson, wearing a ski mask, would tie the victim with ropes or pantyhose, then chide her for leaving a window open and allowing him to break in.

He insisted on knowing details of the victim's sexual life. If she said she was a virgin, there would be sexual contact but no intercourse.

If a victim screamed or struggled, Morgan said, Jackson would smother her with a plastic bag or hold her under water in the bathtub, then revive her.

Some were found on their patios the next morning by young newspaper carriers. Others were put into the trunks of their cars and driven to other locations in Columbus.