I'm walking towards the Torelli's Theorem.I started from scratch! I did not even know what a divisor was in a Riemann surface. I currently went through Abel's Theorem, theta divisor... Now I am reading the proof of the following theorem: 


Theorem 2.25: The theta divisor $\Theta$ of the Jacobian variety $J(R)$, the subvariety $W^{g-1}$ and Riemann's constant are related by following equality: 


$\Theta=W^{g-1} + [k]$.


In the reference I'm using [https://www.amazon.com/Advances-Moduli-Translations-Mathematical-Monographs/dp/0821821563](http://rads.stackoverflow.com/amzn/click/0821821563)


After this theorem 2.25 is written: This theorem implies that the polarization of the Jacobian variety 
is given by the line bundle $[W^{g-1}]$. 


I need to read about polarization of the Jacobian variety. Right now I have another very good reference *Compact Riemann surfaces* (Raghavan Narasimhan), But I did not find out about polarization of the Jacobian variety in this book. 


I would like references on the subject. Thank you!



Polarization of the Jacobian variety
Perhaps <http://jmilne.org/math/articles/1986c.pdf> helps you. Theorem 6.6 is the principal polarisation of the Jacobian.


