TITLE: What is Tropicalization, and how is it applied
QUESTION [20 upvotes]: My question is:
What is Tropicalization, how is it done, and what are some basic applications of it?
motivation
I am interested especially in how questions about enumerative algebraic geometry translate into the tropical world and how information obtained in the tropicalization reflects back on the original question.
This rather general question is similar to earlier questions I asked about integrable systems and about categorification. There are some relevant Wikipedia articles but while interesting I don't find  them sufficient, and several point of views from MO participants can be enlightening and lead to a good resource.
A related MO question Why tropical geometry?

REPLY [5 votes]: One may also consult the book-in-progress by Diane Maclagan and Bernd Sturmfels
at this link:
Introduction to Tropical Geometry. The first five chapters are available as of
this summer.