From the introduction of the editors:

Petr Janský discusses the difference between legal, illicit and illegal financial flows out of poor countries and how they can be measured. He describes two main groups of data models and interprets their main figures. For him, the most detailed and suitable measure is the Financial Secrecy Index (published by Tax Justice Network). Janský explains how this index is constructed, on what data sources it is based and which methodical problems are connected with it.