Victor Klemperer (9 October 1881 – 11 February 1960) worked as a commercial apprentice, a journalist and eventually a Professor of Literature, specialising in the French Enlightenment at the Technische Universität Dresden. His diaries detailing his life under successive German states -the German Empire, the Weimar Republic, Nazi Germany and the German Democratic Republic- were published in 1995. His recollections on the Third Reich have since become standard sources; extensively quoted by Saul Friedlander, Michael Burleigh and Richard J. Evans.
Although the book consists of two volumes (615 and 750 pages), it is one of the most fascinating books I have ever read. His style of writing is so descriptive that one has the feeling that one lives with him from 1881 until 1918! I highly recommend this work!