Book excerpt: The first contribution reviews the occurrence of xanthine alkaloids in the plant kingdom and the elucidation of the caffeine biosynthesis pathway, providing details of the N-methyltransferases, belonging to the motif B' methyltransferase family which catalyze three steps in the four step pathway leading from xanthosine to caffeine. The second contribution in this book provides a background on the molecule and related compounds and update knowledge on the most recent advances in Iboga alkaloids. The third contribution presents a comprehensive analysis of frequently occurring errors with respect to 13C NMR spectroscopic data and proposes a straightforward protocol to eliminate a high percentage of the most obvious errors.