[For the entire collection see Zbl 0715.00010.]
The equivalence of \(k\) mutually orthogonal latin squares of order \(n\) to a \((k+2)\)-net of order \(n\) and of \(n-1\) such squares to a projective plane motivates this chapter. The mutually orthogonal latin squares of small order (up to 15) and the corresponding projective planes and their properties are surveyed. However, since the book went to press Lam et al. have shown that the known desarguesian plane, the translation plane, its dual, and the Hughes plane are the only projective planes of order 9 and that there is no projective plane of order 10. This is discussed in an addendum. Digraph complete sets of latin squares and incidence matrices as well as complete sets of column orthogonal latin squares and affine planes are surveyed. A good discussion is given of the Paige-Wexlen latin squares and the problem of deciding which projective planes of a particular order are represented by a given complete set of mutually orthogonal latin squares.