This is the TAOCP book I see referenced/recommended the least, and admittedly it is the one I have found least useful as a reference so far. But, for me, it was the most enjoyable read of them all. The first two-hundred pages deal with methods for generating random numbers and checking if a sequence is sufficiently random. At times, Knuth gets quite philosophical, and the main takeaway of this chapter is that there isn't a totally well-defined concept of what a random sequence should be, at least as far as computers are concerned. The second chapter of this volume deals with arithmetic, starting with methods for representing floating-point numbers in memory and then diving into algorithms for adding, multiplying, factoring, etc. A detailed analysis of every single algorithm is given, and Knuth doesn't just restrict himself to real numbers; this chapter discusses generalises many of these operations to modular arithmetic, polynomials, matrices, and power series as well. All in all, this volume concerns the concepts that modern programmers take for granted on a day-to-day basis: the ability for a computer to perform basic arithmetic operations quickly.