This volume presents the first part of a synopsis and revision of Amphora Ehrenberg ex Kützing sensu lato, and contains taxa that share dorsiventral valve asymmetry and in the past were considered as members of this genus. The synopsis includes taxa from the following genera: Amphora sensu stricto (or subgenus Amphora Cleve), Halamphora (Cleve) Levkov (or subgenus Halamphora Cleve), as well as selected species from the subgenera Amblyamphora Cleve Psammamphora Cleve and Diplamphora Cleve, and species from the recently established genera Eunophora Vyverman, Sabbe & Mann and Colliculoamphora D. M. Williams & Reid. The synopsis covers mostly species from the temperate zone of the northern hemisphere, including Europe, Asia and North America, but also many localities in Africa and South America. Special attention was paid to taxonomy and distribution of the species of Amphora sensu stricto in the ancient lakes, Baikal, Tanganyika, Ohrid, Prespa, Biwa, Aoki and Hövsgöl. It also includes species primarily known from North America and/or North Asia and several marine and brackish water species from European coasts and estuaries. The synopsis includes observations of species described by Kützing, W. Smith and Hustedt, Reichelt, Østrup, Krasske, Cholnoky, Giffen, Foged, J. Carter, Hohn & Hellerman, Patrick, & Freese, Haworth, Gasse, Krammer, Metzeltin and Lange- Bertalot based on type material. More than 240 taxa were observed and 79 new species were described as new to science. Of these, 62 belong to the genus Amphora, 16 to Halamphora and one to Eunophora. The species are illustrated with LM and SEM microphotographs arranged on 262 plates. Detailed explanations of morphology of valves and frustule as well as ultrastructure are given on more than 240 pages. After each genus or subgenus, a key for identification is provided.