The many facets of Libya's mysterious and quixotic Col. Muammar Qaddafi

''Qaddafi might have fielded hit squads against his own dissidents in Europe before, but senior European officials are confident he is no longer doing so.'' Such was the view of an experienced European analyst of Libyan affairs, who went some way toward explaining how Europe's statesmen have learned to live with the Libyan leader in spite of his past adventures.

One example of how far thinking here in Britain has moved in this regard was given a few weeks ago, when Libyan security leader Ahmad Qadhafadam was given top security during a visit to London, sources close to the British Foreign Office report.

Qadhafadam was until recently feared and hated by security men in most West European capitals. But when he came here in October, it was on a mission Britain's leaders heartily approved of: He was here to talk to an envoy of Egypt's President Mubarak, who had lately succeeded Sadat.

It was during that meeting that the two sides agreed to lessen the tensions previously building up along their common border. And it was then that the Libyan leadership first voiced the possibility of pulling Libyan troops out of Chad, the same source said.

To unravel the tangle of Libya's foreign adventures and initiatives since Colonel Qaddafi's officers came to power in 1969, Libya specialists advise the novice to consider them in the context of the late Egyptian President Gamal Abdel Nasser's theory of ''the three circles of the revolution.'' These circles are, respectively: the Arab, the Islamic, and the African fields of operation.

Qaddafi's first emphasis after 1969 was his Arab policy, and the principal means he sought to use was repeated and often ill-considered attempts to unify with other Arab states. These included, at different times: Egypt, Syria, Tunisia, and North Yemen.

By 1972 and 1973, however, repeated failures had turned the dream of unification ''from on top'' sour. The youthful leader's great mentor, Nasser, was dead. And Qaddafi started to turn his attention to subverting Arab societies (principally Egypt) ''from below'' until a regime amenable to unification could be instituted.

His first major reported use of terror tactics against Anwar Sadat's Egypt dates back to an attack by Muslim fundamentalists on Cairo's technical military academy in April 1974, which killed 30 people. In the following years the Egyptian government blamed a series of major and minor terror incidents - and even, less justifiably, the food riots of January 1977 - on Libyan provocation.

With President Sadat dead, Colonel Qaddafi appears to be hoping that relations with Egypt can now be kept calm. But he must meanwhile consider his policy elsewhere in the ''Arab circle.'' He has a 15-month ''total unification'' bid with Syria grinding away slowly, but meanwhile deep disputes with neighbor Tunisia and conservative Saudi Arabia continue to fester.

The Tunisians have been especially bitter toward Colonel Qaddafi ever since leaders of a failed uprising in the Tunisian oasis of Gafsa confessed to Libyan backing.

Even in regard to the Palestine Liberation Organization, Colonel Qaddafi's policies have not been all smooth sailing. His relations with the major Palestinian guerrilla group, Fatah, have often been stormy. In 1974, Fatah cracked down on Qaddafi's attempt to build up his own, totally loyal Palestinian group.

Since then, he has had to content himself with patronizing a number of small existing groups who are also able to find willing backers elsewhere. The series of worldwide, Palestinian-executed terror operations in the mid-1970s in which Libya collaborated thus achieved little. And all sides gradually agreed to concentrate on anti-Israeli activities.

Colonel Qaddafi's attention has been turned only intermittently to the purely Islamic field of operation. He reportedly supplied arms and money to Muslim secessionists in the Moro Islands, in the southern Philippines during the early '70s. But in 1976, Imelda Marcos, wife of the the Philippine President, made a bold personal visit to Tripoli to persuade him to desist. The Moros movement later split into three factions, and by 1977 Colonel Qaddafi lost interest.

If Colonel Qaddafi's forays into worldwide Islam have generally been short-lived, his concentration on black Africa has exceeded even that of Nasser. His much-publicized recent interest in neighboring Chad dates back, according to some experts, as far as 1970.

In that year, a coup attempt against Qaddafi was planned to be bolstered by mercenaries flying in from Chad. Since then, he has seen his southern neighbor as a sort of underbelly, whose security is vital to his own. But his recent pullback of troops he sent to Chad in 1980, even if not yet a total withdrawal, does signify a new flexibility toward that strife-torn country.

Apart from these two well-publicized cases of ''military help to friendly regimes,'' as the Libyans term it, Libya has given consistent and public help to African liberation movements such as the African National Congress, SWAPO and the Polisario Front.

Despite this catalog of activities, European statesmen appear confident that Qaddafi might now be pulling back across the board of his many international activities.

Though sometimes the victims of his activities in the past, these diplomats are reliably reported to believe that a means of coexistence can be found. And, over the past few months, they have not been proved wrong.