this book describes the development of pbpk modeling for toxic compounds over the past eight decades and the current uses of these models. the book provides background on the basics of pbpk modeling. following an introductory chapter on pbpk modeling, a series of chapters reviews pbpk model results for various classes of compounds with coverage of historical development, specific modeling challenges, and current practices. comments describe the use of these pbpk models to support pharmacodynamic modeling for toxic responses and future directions for modeling.