[Koshkin]

I have nothing against using color in books. I think that, for example, Topology Illustrated by Saveliev got this right. The use of color is especially helpful in presenting objects (not text) when the density of information is high, e.g. in schematic images found in books on cell or molecular biology. Turning an otherwise excellent text into a shiny toy, on the other hand, only serves to damage its reputation in the eyes of a serious reader (but, sure, not necessarily a younger student who may be used to or even appreciative of shiny things).