What is it called

When you just happen onto something that turns out to be something you are glad to have, but never thought to look for? My latest read, Our Lady of the Lost and Found is in that category. The big advantage a library or brick and morter bookstore has over Amazon or Bookmooch is having displays to catch your eye, to make you buy what you didn't come seeking. One thing that has given my some good luck (and some duds) on bookmooch is to look at the inventory of the people from whom I am mooching. I know I always like it when folks mooch more than one book from me, because the postage doesn't go up substantially with the second book, and I get the extra point more or less for free (for me, the books themselves are worthless--I've read them, I don't want them any more and if they don't get mooched, they get given way). This book is about a middle-aged writer somewhere in the US who one day finds Mary (as in Jesus' mother) in her living room. Mary needs some R&R and thinks this house, with this woman is the place to get it. The woman describes herself as a "small "c" christian"--with some generic Christian beliefs, but mostly not a religious person. While Mary is there,she talks about what she has been doing in the last 2000 years and we get stories about some of her apparitions. It's not really a religious book, but it has religion and philosophy in it, and is an interesting story. It will make its way to my bookmooch stack eventually. Email me if you want it.