Johannes Rau: Social Democrat challenger to Chancellor Kohl in 1987, has by far the greatest popular support. But that may not help him much. Talks last year with a view to proposing Mr Rau, 63, as a jointly agreed candidate came to nothing when Mr Kohl's party took fright at the possible electoral implications of such a deal. His only chance of winning is a large-scale revolt by the Free Democrats against Mr Herzog. Most observers believe this unlikely.
Hildegard Hamm-Brucher: Free Democrat. Aged 73, she retired from politics in 1990. Originally a stalking horse candidate, a symbol of the FDP's indignant refusal to contemplate voting for Steffan Heitmann. Once he was dropped, the pressure from the CDU coalition partner to drop her was so insistent the FDP stubbornly clung to her. She is likely to drop out before the last round of voting, with most FDP members switching allegiance to Mr Herzog.
Jens Reich: A 55-year-old molecular biologist, was a leading light in the pro-democracy movement in East Germany in 1989. He himself admits that his chances of becoming president are slim or non-existent. His supporters - a group of intellectuals - emphasise the importance of having an east German president of a united Germany, to help the healing of wounds. Mr Reich, who enjoys considerable respect for his personal integrity, represents the non-party option.
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