A personal view on developmental and comparative immunology: What, how and why?

What are the future directions of the fields of developmental and comparative immunology? In thinking through this question as I write, I find myself marvelling at the very long ways that we have come since I began as a PhD student some 50 years ago. I think that we cannot know what technical and theoretical advances will emerge in the future, nor will our initial aims survive the realities of what appears in our sights, often from unexpected directions. I feel that we should not allow what we already know about some well-studied systems to blind us to the wide range of possibilities, and that remaining a humble seeker helps the uptake of new realities. Finally, it would be good to try answering the whole range of questions about developmental and comparative immunology, from what to how to why.