The best--and presumably the brightest--of the friends of Henry Kissinger '50, will gather at the Colony Club in New York tomorrow night to celebrate his 50th birthday. Guido G. Goldman '59, professor of Government, will host 150 guests in honor of his former thesis adviser.

"Professor Goldman handled all the details personally," a source at the West European Studies Center said yesterday. "It will be a very Washington-oriented party, Kissinger has been back at Harvard very little, so most of his friends are in other circles," she said.

Goldman could not be reached yesterday for comment.

Goldman wanted as little public attention as possible, the source said. None of Goldman's faculty colleagues would comment yesterday on whether they had received one of the engraved invitations to Saturday's black-tie affair.

Goldman's friendship with Kissinger dates from Kissinger's years on the faculty, when Goldman wrote an international relations thesis under him. Kissinge was the inspiration behind many of the West European Studies programs which Goldman now administers, the source said. Kissinger sometimes uses Goldman's New York apartment on visits, according to the Washington Post.

Among the invited guests are Nancy Maginnes and London Times correspondent Henry Brandon. Maginnes is Kissinger's most serious romance, leading to the unconfirmed rumors that he may announce their engagement on Saturday.