The Official SAT Prep Book, released by the College Board, is the most popular SAT prep book available. Additional options include Kaplan SAT Strategies, Cracking the SAT and The SAT Prep Black.
The SAT college entrance exam was first developed as an Army IQ test. Carl Brigham, one of the men who developed the Army Alpha test, published "A Study of American Intelligence" based on the results. Harvard University's dean hired Carl Brigham to develop a version of the Army Alpha exam to determine which applicants deserved academic scholarships. By 1934, Harvard required all university applicants to take the SAT to determine admissions eligibility. Today, Ivy League schools still require applicants take the SAT to be attendance eligible.