Among the main goals of run 2 of the Fermilab Tevatron are improved 
measurements of the properties of the top (or "truth") quark. Although 
run 1 ended in 1996, the final results on the top anti-top quark pair 
production cross section have only recently been published by the CDF 
(2001) and DZero (2003) collaborations. I will review in some detail 
the measurements from the DZero experiment of the top anti-top quark 
pair production cross section in the nine analysis channels, compare 
the final result with various theoretical predictions, and comment 
briefly on the expectations for run 2 and the LHC experiments.