The 40-year-old unemployed Baltimore man who was charged Thursday in connection with the kidnaping of a Maryland National Bank employe, had planned to write a book about just such a kidnaping, according to an FBI affidavit released today.

The FBI said that Ronald Joseph Hackett had telephoned a neighbor who used to work for the Equitable Trust Co. twice in Dec. 21 to discuss various bank security procedures.

After the neighbor had explained banking methods of marking money and the availability of money during late evening hours, Hackett allegedly told him "he intended to write a book about the kidnaping of a bank manager's wife," according to ageny Joe H. Hardage.

After reading the FBI affidavit and listening to reports on Hackett's personal life, U.S. District Court Magistrate Frederic N. Smalkin said today the facts of the case showed "desperate premeditation." He ordered Hackett held at the Baltimore City Jail on $100,000 bond.

Andrea Bowling, 28, was kidnaped from her trailer home at gunpoint Wednesday night and dragged off in front of her husband and two small children. She disappeared for 11 hours while a series of phone calls were placed to her boss, Ralph Wood. Wood was instructed to put $250,000 into a briefcase and to dangle the briefcase in a blue canvas bag from a middle railing of the Back River Bridge in Essex, north of Baltimore.

She was released unharmed after the ranson had been placed as demanded.

Today's FBI affidavit says a security man for the C&P Telephone Co. traced the last phone call about the ransom to Hacketths telephone.