Ugogo na ardhi yake “The Gogo and its land” is the first geography book wrote in Kiswahili about the Ugogo region in Tanzania (former Tanganyika territory). The book gives precious details with numeric tables about populations, crops and environment. The linguistic terms about the land and especially the soil are given in a Cigogo/Kiswahili translation. The precise administrative organization of the land is also described. Ugogo na ardhi yake will be a valuable reference book for historians, geographers and all the people interested in the history of geography and ecology in the beginning of the 20th century in Tanganyika. It is worth to mention that Mathias E. Mnyampala is a pioneer in the history of ecology studies in East Africa also he is more known as a poet and lawyer. This manuscript remained for more than forty years without being printed after the death of the author in 1969. It was discovered in 2007 in Dodoma by Dr. Mathieu Roy in collaboration with TUKI (TATAKI now at the University of Dar es Salaam) and the author's son Mr. Charles M. Mnyampala who kept the manuscript as a collection of unedited papers for a long time and got it edited in 2014 by Dr. Aurélia Ferrari and Dr. Mathieu Roy from INALCO - Alliance Sorbonne Paris Cité, France.