Five years after we began our world trip, Luna got an owl announcing the retirement of Hagrid, the Care of Magical Creatures Professor, and inviting her to take over the position.  She decided to accept the invitation, for by now she was ready to have children and she thought it would be better for them if we settled down in Hogwarts instead of dragging them around the world with us.

A year later our first child was born – a boy – and Luna named him Xenophilius after her father.  "The name means one who likes outsiders," she explained to me, "an appropriate name for a Ravenclaw."  A year after that, our second child was born – a girl – and I named her Hermione after our mentor.  While Luna worked, I stayed home to look after our children, and I home-schooled them.  I decided to give them a good grounding in Muggle science; so I bought mathematics and science textbooks from a Muggle bookstore to teach both myself and my children.

As we had hoped, our son was invited to study at Hogwarts and was sorted into Ravenclaw.  The following year our daughter too would be attending Hogwarts.  Since our children would no longer need so much of my time, I wanted to be gainfully employed; so I asked the Hogwarts Headmaster to create a new course – Muggle Science with Applications to Magic – and to let me teach it, starting at the beginning of the following year.  He was reluctant at first, but a few weeks later he changed his mind.  Our son had regaled everyone he met about the cool things I had taught him, and they had prevailed upon the Headmaster to hire me to teach them too.

For the first year of my employment, I taught biology to all the students, beginning with comparative animal behaviour.  Each year I introduced a new subject to the students who had taken the previous ones until, after seven years, all the students who had passed my course each year of their studies knew enough to enter a Muggle university in mathematics or any of the natural sciences.  Some of them did, mainly Ravenclaws but also a few from each of the other Houses.  Mingling with Muggle students, they learned a great deal about the Muggle world.  They were fascinated with Muggle technology, especially computers, but the discovery of theirs that made the greatest impression on them had nothing to do with technology.  It was to have a profound effect on the magical community.