The book "Geochemical Modelling of Igneous Processes - Principles and Recipes in R Language" provides a comprehensive introduction to the application of the R programming language for the geochemical analysis of (meta-)magmatic rocks. It is aimed at advanced students and researchers engaged in whole-rock geochemistry. The first part of the book covers fundamental aspects such as data import and export, the calculation of common indices, and graphical representation in R. The main section introduces various modeling techniques used to analyze processes such as partial melting, fractional crystallization, and binary mixing. Readers will gain a solid theoretical foundation for forward and inverse modeling, supplemented by practical exercises that address typical challenges in geochemical research. Finally, practical examples demonstrate how realistic models can be developed to simulate natural systems. The appendices provide an introduction to the basics of the R language and the open-source package GCDkit for interpreting geochemical data.