Jo Walton answers the question posed by the title for a bit more than 100 books in this collection of brief reviews devoted to re-reading. As I read through, I enjoyed thinking of how the emphasis could fall on each of the words in the title, although the cover design clearly places it on the third: What Makes This Book So Great. But it’s fun to hear Walton put it elsewhere in various essays. What Makes This Book So Great. What Makes This Book So Great. What Makes This Book So Great.

All but two of the short essays are collected from columns that ran on Tor.com between 2008 and 2011. They are pithy, to the point, and occasionally refer to comments made in answer to previous columns.

Walton reads as a prodigious rate. At one point, she notes that a day seldom goes by that she does not finish a book, and if she devotes the day to reading, she is perfectly capable of getting through six or seven novels. In one of the columns, she mentions readers who have commented and noted that they seldom re-read books. They feel there are so many books to read, and a limited lifetime to do it in. Walton, by contrast, says that she grew up with a finite number of books and still has the feeling that she might run out. I think her speed, about five times as fast as even a devoted reader, explains the difference.

In her discussion of George Eliot’s Middlemarch, Walton regrets that Eliot couldn’t singlehandedly invent science fiction. It’s not as far-fetched as it seems. Jules Verne was being translated into English at that time. H.G. Wells would be writing just 25 years later. Eliot appreciated how science and technology were changing the world. Many of the things she does in Middlemarch have science-fictional aspects. But what could have been! Walton writes, “… Dorothea’s story at least ends happily, if unconventionally. That is, unconventionally for a Victorian novel. She doesn’t get to be the ambassador to Jupiter, more’s the pity.”

Many of the books that she writes about in the book are out of print, or otherwise obscure. She likes books that expand the possibilities of what can be done within the genre. She mentions authors she finds brilliant and their lack of commercial success difficult to fathom, such as Terry Bisson. She also likes books that aren’t, as she says, like anything else. She says that, for example, about The Interior Life by Katherine Blake, Random Acts of Senseless Violence by Jack Womack, or Red Shift by Alan Garner.

Walton takes extended looks at C.J. Cherrryh’s Union-Alliance books, at Lois McMaster Bujold’s Vorkosigan series, and at Steven Brust’s Taltos series. I skipped the 50 pages or so devoted to Brust because I am planning to read several of them later this year. She also looks at several books in a row in which time travel is a major element, but ultimately self-defeating. I’m curious what she thinks of John Crowley’s “The Great Work of Time.” She has interesting takes on Heinlein’s earths as dystopias, and her essays on Samuel R. Delany give good entry points to a famously challenging author.

Walton writes her reviews in direct, declarative sentences. The one thing that would really improve the book is an index, preferably a long one compiled with a dry, perhaps even Borgesian, sense of humor. That’s the only complaint I have with this collection. Spending time with someone so knowledgeable and so enthusiastic is a great pleasure. And that’s what makes this book so great.