Is the null-graph a pointless concept?
-- Frank Harary and Ronald C. Read, Lecture Notes in Mathematics, 1974, Volume 406/1974, 37-44.

The graph with no points and no lines is discussed critically. Arguments for and against its official admittance as a graph are presented. This is accompanied by an extensive survey of the literature. Paradoxical properties of the null-graph are noted. No conclusion is reached.