A significant factor in the admission processes of nearly all colleges and universities in America.
A high score increases your chances of being accepted to the school of your choice.

Is there more than one SAT? Am I required to take all of them?

There are two different types of SAT tests: the SAT Reasoning Test and SAT Subject Test.
The SAT Reasoning Test includes Critical Reading, Math, and Writing sections, and is required by most colleges and universities.
The second kind of test is the Subject Test (also known as the SAT II’s) which measures aptitude in specific subject areas.
The more selective colleges (like the Ivy League schools) may require several different Subject Test scores in addition to the
Reasoning Test score.

What else should I know about the SAT Reasoning Test?

The first section of the SAT will always be a 25-minute essay section, and the last section will always be a 10-minute
multiple-choice writing section. The other six 25-minute and two 20-minute sections can appear in any order.
There is also a 25-minute section, known as the variable or equating section, which is not scored and can be either
a critical reading, math, or writing multiple-choice section. This section does not count toward the final score,
but is used to test new questions for future editions of the SAT and to ensure that scores on new editions of
the SAT are comparable to scores on earlier editions of the test.
Test takers sitting next to each other in the same testing session may have test booklets with entirely different sections.