One of the most exciting subjects in Primatology are that of the origin of primates and their early evolution. Mostly because many of the "big questions" are still far away from answered.
One of those quetsions is about the geographical and chronological origin of primates.
To give you a little introduction to some these issues I want to present you a (very rough) tree which shows the relationship between the larger groups of primates and there estimated dates of divergence:
Janecka, J., Miller, W., Pringle, T., Wiens, F., Zitzmann, A., Helgen, K., Springer, M., & Murphy, W. (2007). Molecular and Genomic Data Identify the Closest Living Relative of Primates Science, 318 (5851), 792-794 DOI: 10.1126/science.1147555
Eizirik et al. (2004) Molecular Phylogeny and dating of early primate divergence. In: Ross, C.F., Kay, R.F. Anthropoid origins. New Visions. Kluwe Academic/Plenum Publications, New York.