Many things in the natural world work so well that they seem to have been designed. But by what? Could nature itself, by processes including those of evolution, be the designer? Or must their complex structure and function be attributed to some intelligent designer or God? Is natural design compatible with intelligent design? How good is the argument from the presence of design to an intelligent designer? And if we could legitimately infer the probable existence of an intelligent designer from the presence of design in the natural world, what could we then infer about that designer's nature?