The 'chemometrics' package in R provides functions for multivariate statistical analysis, diagnostics, multivariate calibration, cross-validation, and clustering, primarily for chemometric applications. It is a companion to the book "Introduction to Multivariate Statistical Analysis in Chemometrics" by K. Varmuza and P. Filzmoser. The package includes tools for data transformation, such as additive logratio (alr), centered logratio (clr), and isometric logratio (ilr) transformations, which are used to handle compositional data. It also offers functions for principal component analysis (PCA), partial least squares (PLS), and robust PLS (PRM), along with methods for cross-validation, bootstrap, and outlier detection. The package includes datasets for various chemometric applications, such as glass, ash, cereal, and phenyl, which are used for demonstration and analysis. The package supports robust statistical methods, including those based on the MCD estimator, and provides functions for plotting and visualizing results, such as Mahalanobis distance plots, PCA diagnostics, and cross-validation plots. The package is available on CRAN and is licensed under GPL (>= 3).The 'chemometrics' package in R provides functions for multivariate statistical analysis, diagnostics, multivariate calibration, cross-validation, and clustering, primarily for chemometric applications. It is a companion to the book "Introduction to Multivariate Statistical Analysis in Chemometrics" by K. Varmuza and P. Filzmoser. The package includes tools for data transformation, such as additive logratio (alr), centered logratio (clr), and isometric logratio (ilr) transformations, which are used to handle compositional data. It also offers functions for principal component analysis (PCA), partial least squares (PLS), and robust PLS (PRM), along with methods for cross-validation, bootstrap, and outlier detection. The package includes datasets for various chemometric applications, such as glass, ash, cereal, and phenyl, which are used for demonstration and analysis. The package supports robust statistical methods, including those based on the MCD estimator, and provides functions for plotting and visualizing results, such as Mahalanobis distance plots, PCA diagnostics, and cross-validation plots. The package is available on CRAN and is licensed under GPL (>= 3).