R Package rethinking: Statistical Rethinking Course and Book. This R package accompanies a course and book on Bayesian data analysis (McElreath 2016. Statistical Rethinking. CRC Press.). It contains tools for conducting both MAP estimation and Hamiltonian Monte Carlo (through RStan - These tools force the user to specify the model as a list of explicit distributional assumptions. This is more tedious than typical formula-based tools, but it is also much more flexible and powerful.