Foreword.- Part I - Germline developmental potential.- 1. Primordial germ cells to EG cells, Peter Donovan.- 2. Pluripotent stem cells from SSCs, Marco Seandel, Ilaria Falciatori, and Shahin Rafii.- 3. ES cells to gametes, Sonya M. Schuh-Huerta and Renee A. Reijo Pera.- Part II - Spermatogonial stem cells.- 4. Morphometric description of the SSC pool in mammals, Dirk G. de Rooij.- 5. Spermatogonial stem cell transplantation and culture, Jonathan A. Schmidt and Ralph L. Brinster.- 6. Spermatogonial stem cell culture and in vitro assay, Makoto C. Nagano and Jonathan R. Yeh.- 7. Molecular signaling in SSCs, Olga M. Ocón-Grove and Jon M. Oatley.- 8. Spermatogonial stem cell niche, Shosei Yoshida.- Part III - Translation and regenerative potential of spermatogonial stem cells in higher primates.- 9. Gonadotoxic therapies: effects on spermatogenesis and fertility, Gunapala Shetty, Gensheng Wang, and Marvin L. Meistrich.- 10. Testicular xenografting, Stefan Schlatt, Jose R Rodriguez-Sosa and Ina Dobrinski.- 11. SSC transplantation in primates, Brian P. Hermann and Kyle E. Orwig.