ABSTRACT
Avian phylogenetics is currently in its infancy, and paradoxically it is also nearing maturity. By infancy I mean that we do not currently know much about the relationships among birds, and by maturity I mean that within a few years we will know most of what there is to know. The reason for this apparent paradox lies in the rapidly increasing ease of gathering and analyzing molecular data. Our ignorance is largely a matter of our not yet having gathered enough DNA sequences or other molecular data for enough species, and that condition is being remedied at an increasing rate. If I had written this chapter a year or two from now, I would have been able to cite studies incorporating perhaps twice the data so far in published form-this purely from yet-unpublished studies of whose existence I am now awareand I would have been able to say much more about the structure of the avian tree. But the editor was not anxious to follow that schedule, and so we press on with what is currently available.
