Preface; 1. Introduction; 2. XYZ and Pc phenomenology; 3. Color forces and constituent quark model; 4. Hadron molecules; 5. Light scalar mesons; 6. Mass formulae for P-wave, qq mesons; 7. Compact tetraquarks; 8. The Xu Xd puzzle; 9. Y states as P-wave tetraquarks; 10. Pentaquark models; 11. Tetraquarks in large N QCD; 12. QCD sum rules and lattice QCD; 13. Phenomenology of beauty quark exotics; 14. Hidden heavy avour tetraquarks – overview; 15. Tetraquarks with double heavy quarks; 16. Outlook; Appendix A. Low energy p – n scattering amplitude; Appendix B. Wigner's 6-j symbols; References; Index.
