This audiobook was a lot of fun and kept me entertained and absorbed to the end -- which is saying something because I'm not in the target audience. I don't believe in parallel universes.

The characters in this book say that it's science, but I'm sorry, just because a physicist came up with a theory to explain some equations, that doesn't mean it's science. This isn't a theory you can verify, after all. To me, the theory that a new universe is created every time you make a decision, besides seeming wildly unlikely, takes away a lot of human agency. What does it matter what choice you make if in another universe you made a different one?

In fiction, it also takes away from the story -- why should I care about this particular character if another character just like them is doing something different in another universe? Why should I care about this particular set of choices? But if your choices do make a difference -- you've got a story.

The way parallel universes come up in The Midnight Library is that Nora Seed has some sad things happen and decides to end her life. After she attempts to do so, she finds herself in the Midnight Library. It's a library with infinite shelves where the time is always midnight. She sees her old school librarian there, who tells Nora this is her chance to undo her regrets. Each book in the Midnight Library represents another life that Nora could have lived. Choosing a book and reading it takes Nora into another life in an alternate universe where she made a different decision somewhere along the way. If she finds a life that she likes, she can stay.

So, in this context, the alternate universes do provide a fascinating way to explore Nora's regrets. She quickly sees that if she had done what other people wanted her to -- things didn't always turn out so wonderful. So can she find the life she actually wants?

It does work as an interesting frame, but I still have trouble with the logistics. Nora dropped into lives without the memories of the alternate-Nora from that life. A lot of good it would do to be a polar researcher if you know absolutely nothing about the topic, after all. And I kept wondering, Where did the alternate Nora go? And wouldn't it be a shame to have fallen in love and gotten married and had a child if you couldn't remember doing any of those things? So it didn't seem like a fair trial of the alternate lives. And without having actually made the choices that got her there, they talked about Nora's "root life" -- as if that Nora is the real person and her alternate selves are disposable.

But if you think of this book as a version of "It's a Wonderful Life" -- a vivid look at what would have happened if things had been different -- and don't get too bogged down in the details (as I tend to do), it is always fun to speculate how things might have turned out if you had made different choices.

This book also helped me realize that I've outgrown my regrets. There was a time when I wondered how life would have turned out if, for example, I hadn't dropped out of a PhD program in mathematics. But after my divorce, that all seems like water under the bridge. My divorce was something that got me wondering if I could have done something differently to prevent it (even though it was my ex-husband's idea). But now, twelve years after the divorce was final, my career as a librarian is blossoming -- and if I hadn't gotten divorced, I would have been content to continue to work part-time. But because I got my library degree and became a librarian, I got to serve on the Newbery committee, and just this week, I got word that I landed my dream job as Youth Materials Selector for my whole public library system. Life is good! So who needs regrets?

Still, this book, and this interesting story of Nora and many different things she might have done, is what got me thinking about how nice it is to live without regrets. So if you can keep yourself from thinking too much about the mechanics, I do recommend this book.