The goal of this new edition is the same as for the first edition ”to address the fault detection and isolation topics from a computational perspective“, by covering the same important aspects, namely, (1) providing a completely general theoretical treatment of fault and model detection problems for linear time-invariant systems; (2) presenting the best suited numerical approaches to solve the specific computational problems; (3) providing supporting software to solve the analysis and filter synthesis problems. In this second edition, the changes in the theoretical presentation are minor and all known errors and typos have been corrected. The major difference to the first edition is in the underlying computational support, which is now based on software developed in a relatively new language called Julia. The presentation of synthesis procedures and examples is similar to the first edition, but it is now interlaced with Julia codes which can be used to reproduce all computational examples and figures presented in the book. An Appendix has been added to cover some basic issues related to using Julia and the new FaultDetectionTools and DescriptorSystems packages.