The Sorgenfrey line S is the
real line with the topology generated by the half open intervals [a,b). R. H.
Sorgenfrey proved that S is paracompact, while S × S is not paracompact, or
even normal. The two main results of this paper are that S × S is strongly
zero-dimensional, and that every real continuous function on S ×S in the first Baire
class for the Euclidean topology of the plane. These results answer questions asked by
P. Nyikos.