This book is based on the 2014 Special Issue 124(3) of Climatic Change. It brings together 16 key papers presented at, or produced, subsequent to the 2010 (3rd) International Workshop on Uncertainty in Greenhouse Gas Inventories. The Workshop was jointly organized by the Lviv Polytechnic National University (http://www.lp.edu.ua/en), Ukraine; the Systems Research Institute of the Polish Academy of Sciences (http://www.ibspan.waw.pl/glowna/en); and the International Institute for Applied Systems Analysis (http://www.iiasa.ac.at/), Austria. This book has been written to enhance understanding of the uncertainty encountered in estimating greenhouse gas (GHG) emissions and in dealing with the challenges resulting from those estimates. Such challenges include, but are not limited to i) monitoring emissions; ii) adhering to emission commitments; iii) securing the proper functioning of emission trading markets; and iv) meeting low-carbon or low-GHG futures in the long term.