Preface -- Chapter 1 Introduction -- Chapter 2 Hierarchical multi-fidelity surrogates modeling -- Chapter 3 Non-Hierarchical multi-fidelity surrogates modeling -- Chapter 4 Sequential multi-fidelity surrogates modeling -- Chapter 5 Multi-fidelity surrogates assisted efficient global optimization -- Chapter 6 Multi-fidelity surrogates assisted reliability design optimization -- Chapter 7 Multi-fidelity surrogates assisted robust design optimization -- Chapter 8 Multi-fidelity surrogates assisted evolutional optimization -- Chapter 9 Engineering Applications -- Chapter 10 Concluding remarks.