A blast from the past. Two items that are not used any more since calculators and computers took over the math.
The book is the 'Handbook of Mathematical Functions', filled with tables and formulas, the size of a telephone book.
The rule is a mechanical analog computer, used for multiplication and division of numbers, and for functions such as roots, logarithms and trigonometry. At highschool, I was impressed by the magic of its operation, and I made several ones from cardboard before getting a real one. In the sixth year, we were the last group that had to use this slide rule at the final exams. The next year, calculators were allowed, which meant the end of the slide rule.
ODC - Theme (19-08-2012): Begins with N