The Number of the Beast is a novel with a reputation for being brilliant, impossible to read, and even a work of supreme authorial conceit. I concede that the latter is possible, and the book has problems, surely; but it’s a fun and easy-to-read (if long) book that I reread often.
There’s a theory that the book is a manual on how to write good fiction. I think theories like this come about because the book doesn’t fit into any familiar categories: there’s no easily defined structure, it’s long, complicated, filled with in-jokes, puzzles, and changing first-person narrators that tell the story. It’s somehow enjoyable despite all that.
I read The Number of the Beast when I was a teenager and had read almost none of Robert A. Heinlein’s other work. Despite knowing I was missing something, I still loved reading about the characters’ escape from their home, their exploring of parallel worlds, and their discovery that the universe is created by blissfully unknowing writers. It’s a commonly stated “fact” that a writer has to explain the action clearly to the reader. As en editor, I’d agree with that, but over-explaining can make a book too pat and predictable. Heinlein has managed to leave much up to the reader and still produce a great story.
I believe he did this by layering the novel so thoroughly and deeply that the reader is aware there’s much on the page that’s just beyond their comprehension just now. One might think, “perhaps this will be clearer on a future reading?” and then move on to the next sentence. The ability to do this while still assuming the reader’s competence is an impressive achievement. The books that followed in the series were far more linear.
The Cat Who Walks Through Walls is more of a sequel to the Heinlein classic The Moon Is a Harsh Mistress than anything else, and To Sail Beyond the Sunset is a biography of the character Maureen Johnson from his “Future History” series. Both are good books, but nothing like the carnival of glorious excess that is The Number of the Beast.
So, in what order should you read them? Do you need to read the corpus of Heinlein’s work before tacking them? In response to that question, I’ve put together a suggested reading order.
The chart below puts the books in an order (the numbers next to each title) that presents the reader with the books most closely related to the world-as-myth volumes. Heinlein’s “Future History” and standalone books (the green and gray rectangles) should be tackled before reading the world-as-myth books into which they lead (the red rectangles). It also alternates easier books with more challenging ones.
You can alter this order based on availability of the books, but the arrows in the chart are a guide to what books lead into others. (The core world-as-myth books should be read last where possible.)
Time Enough for Love is an odd case. While it’s part of the “Future History” books, characters in the book are an important part of the story in The Number of the Beast. Indeed, Number is, in some ways, a conclusion to the story of Lazarus Long. Whether or not Time Enough for Love is a core world-as-myth book is unclear, but but it’s definitely a prelude to the world-as-myth story. As fragmented and uneven as it is, it’s also one of my favorite Heinlein novels.
This article takes some text from my answer to this question on the Stack Exchange network.