¹ Astronomical Institute of the Charles University, V Holesovickach 2, CZ-180 00 Praha 8, Czech Republic
² Astronomical Institute of the Academy of Sciences, CZ-251 65 Ondrejov, Czech Republic

A brief review of current problems in the research of hot emission-line stars is presented. Special attention is paid to problems of reliable determination of basic physical properties of underlying stars and to possible role of duplicity in the whole phenomenon. A preliminary catalogue of OBA emission-line stars in binaries is also included.

To appear in: 2000, ``Interacting Astronomers: A Symposium on Mirek Plavec's Favourite Stars'', Publications of the Astronomical Institute of the Academy of Sciences of the Czech Republic No. 89, Ed. by P. Harmanec, P. Hadrava and I. Hubeny, pp. 9-22
Preprints from hec@sunstel.asu.cas.cz
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