[2] During his studies, he took part in excavations in Kamid al lawz in Lebanon, the Mortuary Temple of Seti I in Qurna, and on Elephantine.

Between 1978 and 1987, Dreyer was a consultant in the Cairo department of the DAI and took part in excavations on Elephantine, in Wadi Garawi, and in Abydos .

In 1987 he received a habilitation grant from the German Research Foundation and accepted a teaching position at the Free University of Berlin.

The scientific importance lies in the fact of finding Egyptian hieroglyphs which predate cuneiform script.

The mentioned hieroglyphs are on small wooden tags applied to the jars, probably marking their origin and "are fully developed", as Dreyer stated.

In 1997 he published his habilitation thesis The Predynastic Royal Tomb Uj in Abydos, and his early written documents, and he became head of the excavations on Elephantine.

At its inaugural meeting, the committee established as its first priority, the completion of the publication of cemetery Umm el Qaab which was left unfinished by Dryer's untimely death.

Das prädynastische Königsgrab U-j und seine frühen Schriftzeugnisse (= Archäologische Veröffentlichungen des Deutschen Archäologischen Instituts Kairo.