Who's who at the Republican convention in Dallas this week

Here's a brief introduction to a few of the principals: Ronald Reagan, George Bush: the top of the list - GOP nominees for president and vice-president.

Howard H. Baker Jr. presides over the convention until the permanent chairman takes over. Mr. Baker, Senate majority leader, retires at the end of the year. He's looking toward the 1988 campaign with high hopes for winning the GOP presidential nomination. In the Senate since 1966. Roots in eastern Tennessee, a state that Reagan carried narrowly in 1980 in a 49 to 48 percent win over Carter.

Robert H. Michel, permanent convention chairman. Minority leader in the US House; represents the 18th District of Illinois in the west-central part of the state. District gave Reagan 62 percent of its vote in 1980. The state went for Reagan 50 to 42 percent.

Trent Lott, chairman of the platform committee. Lott is GOP whip in the US House. He represents Mississippi's Fifth District along the Gulf Coast.

Nancy Kassebaum, another presider at the convention, but a reluctant one until party leaders convinced her that a woman political leader was needed in a conspicuous place at the convention. She's from Kansas and is up for reelection this year. Kansas voted overwhelmingly for Reagan over Carter in 1980, 58 to 33 percent.

Frank J. Fahrenkopf is the Republican National Committee chairman. He comes from Nevada where, when he was state party chairman in 1975, Democrats outnumbered Republicans by 3 to 1. When he left for national party leadership in 1983, the ratio was 2 to 1. He will be largely behind the scenes in Dallas.

Katherine Davalos Ortega, keynote speaker, is treasurer of the United States and a native of Alamogordo, N.M. She worked her way up to become the first woman bank president in California and then returned to her home state.

Priscilla Rakestraw is chairwoman of the credentials committee, which decides who is authorized to attend the convention. She's from Delaware where she is campaign chairwoman for Elise R. W. duPont who is challenging incumbent Democratic Rep. Thomas R. Carper.

Terry Branstad is the governor of Iowa and the youngest governor in the US. He chairs the rules committee, a basically ceremonial post because there's no battle over the nominations, and a convention that sails along smoothly is planned.

Jeane Kirkpatrick is America's ambassador to the United Nations. She speaks opening night as part of the party's strong presentation of its female dignitaries. An outspoken voice on behalf of the President's hard-line foreign policy, Ambassador Kirkpatrick is a specialist in Latin American history and politics. She's also nominally a Democrat.

Margaret Heckler, secretary of the Department of Health and Human Services, entered the Reagan Cabinet after losing her House seat to a liberal Democrat after redistricting. She also speaks Monday evening.

Elizabeth Hanford Dole speaks Tuesday evening after former President Ford's address. She is transporation secretary, wife of Kansas senior Sen. Robert Dole, and is judged by many to be a vice-presidential prospect in the future.

Paul Laxalt, senator from Nevada for 20 years, frequent adviser to the President, obvious choice to place Mr. Reagan's name in nomination Wednesday evening. (California Gov. George Deukmejian will nominate Vice-President Bush.)

Jack F. Kemp, representative of the 31st District of New York, which begins with Buffalo and reaches east toward the Finger Lakes. He, too, has his eye on the 1988 GOP nomination. He is prominent in party counsels as a chief spokesman for ''supply side'' economics. He sold the President on the idea of a massive tax cut to spur the economy, legislation which passed in 1981. He pushed hard to get a platform plank that ruled out any tax increases in the next administration.

Newt Gingrich, representative from Georgia's Sixth District, which approximates metropolitan Atlanta, is the only Republican in the House from Georgia. His district voted 52 percent to 45 percent for Carter in 1980 while Gingrich was winning reelection 59 to 41 percent. Gingrich and Kemp are leaders of a group of junior GOP House members called the Conservative Opportunity Society.