October 5, 1986

THE man with the magical touch was sitting behind his desk the other day sorting mail and choosing 8-by-10 color photographs of himself to be autographed. This was business as usual for him; at least, it seemed so because Dave Johnson was not smiling. Not on a game day. Johnson will not allow himself such irrational pleasures with his team 20 games in front and the race already over. If he is standing behind the batting cage, pacing the dugout, offering a grudging postgame analysis to the media, Johnson reveals only his hardened side. Little more. This is no facade. The man who delivered the Mets from seven consecutive losing seasons to the National League playoff in just three years is blunt, impatient and, some have said, as arrogant as his team. A sense of humor occupies but a small corner of his mind. It is not necessary to peel away layers to know Johnson, the manager. But there are other, more intricate, sides that demand a thorough look, if only because they are part of the whole.

''MY WIFE is the ocean,'' said the Rev. Charles H. McTague, ''and my children are its seamen.'' For almost 10 years now, the 66-year-old Father McTague, as Roman Catholic chaplain at Ports Newark and Elizabeth - part of the Archdiocese of Newark's Apostleship of the Sea - has been holding services for and counseling his merchant seaman ''children'' at the Stella Maris Chapel here and along six miles of Hudson River docks. In an average year, he ministers to more than 4,000 seamen from the 2,400 ships of 54 countries that load and unload at the ports. With frequent same-day unloading and loading - often in a few hours - today's crews spend less time ashore than they did a decade or two ago. Weeks and months at sea leave emotional and spiritual gaps that the chaplain tries to fill.

DRUG testing and counseling programs for all Suffolk County employees may begin as early as next year, county officials say. The testing program has been proposed by County Executive Peter F. Cohalan, who last month vetoed a bill passed by the Suffolk County Legislature that would have banned any drug testing of public or private employees and job seekers in the county. The change in direction - which would seem to pit Mr. Cohalan against a number of county legislators - shifts the county from the verge of enacting one of the nation's strictest prohibitions against drug testing to the growing ranks of governments and private businesses that are considering, or have already begun, testing programs. The Cohalan plan, which is still in the process of being drawn up, would have to be approved by the County Legislature.

DURING the conversion of a rental building to co-op ownership, the tenants' committee is naturally eager to strike the best possible deal with the sponsor. Each tenant is also individually trying to make the best arrangements for himself. Several changes have occurred in the last few months that could be helpful to tenants, collectively and individually, in those negotiations. The changes are new rules established by the New York State Attorney General's office, the impending Federal tax revision and the creation of a special formula for tenants who live in a related cluster of buildings.

THE NAZI DOCTORS Medical Killing and the Psychology of Genocide. By Robert Jay Lifton. 561 pp. New York: Basic Books. $19.95. THE horrifying story of the Nazi extermination policy, under which millions of innocent men, women and children were systematically murdered, should be well known by now. In addition to the official documentation on it, many books have been published and movies and television programs have made it known to people everywhere. Reading ''The Nazi Doctors,'' Robert Jay Lifton's account of the crimes committed by physicians in the German concentration camps, painfully revived my memories of the time I had spent in two of them - memories of which I am unable to free myself, as no survivor of them ever can.