Hugo Thielen (born 1946)^[1] is a German freelance author and editor, who is focused on the history of Hanover, the capital of Lower Saxony, in a lexicon of the city, another one especially of its art and culture, and a third of biographies. He co-authored a book about Jewish personalities in Hanover's history.

Thielen studied German language and literature, philosophy and education at the University of Bonn from 1966, completing with the Staatsexamen in 1971.^[2]: ii He has lived in Hanover from 1973, working as editor and author for various publishing houses.^[2]: ii He worked for Schroedel Verlag, ^[de] a publisher mainly of school readers, until 1981, for the Th. Schäfer Verlag until 1995, also for the Postskriptum Verlag, for Hirschgraben, a publisher of school readers in Frankfurt am Main, for Zu Klampen Verlag [de] in Lüneburg and Springe,^[1] and for Lutherisches Verlagshaus. ^[de] From 1983 to 1995 he was a freelance music critic for the Hannoversche Allgemeine Zeitung. He is^{[as of?]} head of a Verlagsbüro, an office for freelance writers.^[1]

Thielen is co-author (besides Helmut Knocke) of Hanover: Art and Cultural Lexicon, ^[de] a lexicon of Hanover's art and culture,^[2] published in 1994 by Zu Klampen Verlag,^[1] with a 4th edition in 2007. He is co-editor, author and designer of the 2002 Hanover Biographic Lexicon, ^{[de ]}, and of the Hanover City Lexicon. ^{[de ][1]}

First in 1998, Thielen and Waldemar R. Röhrbein, the retired director of the Historisches Museum Hannover,^[3] wrote the book Jewish Personalities in Hanover's History (Jüdische Persönlichkeiten in Hannovers Geschichte). It is organised as a history of the city, beginning in 1303,^[3] with a focus on the contributions of Jewish personalities, rather than individual biographies. Around a hundred persons are described in some detail,^[4] including the principal violinist of the court orchestra, Joseph Joachim.^[3] A second edition, completely revised by Thielen, appeared in 2013, in memory of the November pogroms 75 years earlier.^[4][3]

• Helmut Knocke, Hugo Thielen: Hannover Kunst- und Kultur-Lexikon: Handbuch und Stadtführer. Ed: Dirk Böttcher, Klaus Mlynek, Zu Klampen Verlag 2007^[5]
• Dirk Böttcher, Klaus Mlynek, Waldemar R. Röhrbein (eds.): Hannoversches Biographisches Lexikon. Schlütersche Verlagsgesellschaft [de], Hanover 2002, ISBN 3-87706-706-9.^[6]
• Klaus Mlynek, Waldemar R. Röhrbein, Dirk Böttcher, Hugo Thielen (ed.): Stadt Lexikon Hannover. Von den Anfängen bis in die Gegenwart. Schlütersche Verlagsgesellschaft, Hannover 2009, ISBN 978-3-89993-662-9.
• Waldemar R. Röhrbein, Hugo Thielen: Jüdische Persönlichkeiten in Hannovers Geschichte, completely revised, extended and updated new edition, Hannover: Lutherisches Verlagshaus, 2013, ISBN 978-3-7859-1163-1^[4][7]