Blue book exam
A blue book exam is a type of test administered at many post-secondary schools in the United States. Blue book exams typically include one or more essays or short-answer questions.
Butler University (Indianapolis) was the first to introduce exam blue books. They were given a blue color because Butler's school colors are blue and white, therefore they gave them the name "blue books." 
Sometimes the instructor will provide students with a list of possible essay topics and will then choose one, or let the student choose from two or more topics that appear on the test. Blue books typically contain several sheets of wide-ruled notebook paper.
Dimensions of the book itself is generally 8.5 by 7 inches, composed of two or three ruled leaves, bound in a sheet of paper and held together by staples. Although the color blue is most common, other colors may be used. The "Green Book" is an environmentally friendly green-colored book manufactured by Roaring Spring Paper Products that is the same size as its blue counterpart but is made with 100 percent recycled paper, 30 percent of it post-consumer waste.
Prevalence of blue book exams varies between institutions and between academic disciplines. At many universities, virtually all exams in disciplines such as history or literature are blue book, while at the same universities, disciplines such as geology and math may virtually never hold such exams.[dubious ]