A package for performing Mendelian randomization using GWAS summary data. It uses the IEU GWAS database <https://gwas.mrcieu.ac.uk/> to automatically obtain data, and a wide range of methods to run the analysis. You can use the MR-Base web app <https://www.mrbase.org/> to try out a limited range of the functionality in this package, but for any serious work we strongly recommend using this R package.