Known for his encyclopaedic knowledge of British prehistory, Jacobi authored several key synthetic volumes and worked to catalogue, sequence and reanalyse collections from across Britain and northwestern Europe.
[2][3] Thomas Higham described Jacobi's doctoral thesis, on Mesolithic Britain, as "a monumental and important piece of work that is unlikely to be matched in terms of its detail and broad sweep".
[2][3][4][5] He never adopted computers,[2][3] preferring to maintain his large archive of information from visits to sites and collections across the country in index cards and longhand notes.
This work led to several important results, including the dating of sequences from key Palaeolithic sites such as Geißenklösterle, Fumane, La Ferrassie, and Pataud.
[4] A volume in his memory, No Stone Unturned: Papers in Honour of Roger Jacobi,[9] edited by Nick Ashton and Claire Harris, was published by the Lithic Studies Society in 2015.
After his death, Wessex Archaeology conducted an English Heritage-funded project to digitise this archive as the Palaeolithic and Mesolithic Artefact (PaMELA) database, published in 2014.