It's always fun seeing what other people have on their bookshelves. Here's one of mine. But this isn't just a chance for a quick snoop - what I want to know is

How are the books ordered?

my books

Hint 1 (already stated in comments)

Everything you need is in the picture. There's no knowledge tag and no reference to anything external.

Hint 2

Disaster! My plan to re-organise my entire book collection has hit a snag. What am I going to do with the annoying books that don't fit anywhere?

Random pile of Annoying Books:

Annoying Books

Hint 3 - now with even more clues

As you might have noticed, seven of the eight Annoying Books are annoying for one particular reason. That reason might suggest which printed words on the spines of the books in the main image you should look at very closely. Ultimately, you're seeking an alphabetical ordering.

Hint 4

No sophisticated analysis or exhaustive search is required. There's some easy-to-see feature in plain sight that nobody has picked up on yet. Now I really must have given it away.

  • $\begingroup$ Would a man by the name of rot13(Wbua Qrjrl) be of any assistance? $\endgroup$
    – Brandon_J
    May 4, 2019 at 0:50
  • $\begingroup$ @Brandon_J. Nope, there’s no reference to anything external. Everything you need is in the picture. $\endgroup$ May 4, 2019 at 3:35
  • 1
    $\begingroup$ I have concluded that the Annoying Books are annoying because rot13(gurl ner ylvat qbja). Case closed. Next! $\endgroup$
    – Rubio
    May 10, 2019 at 3:39
  • $\begingroup$ @Rubio They are lie-ers. They just wouldn't say the truth. So annoying! $\endgroup$ May 11, 2019 at 17:30
  • $\begingroup$ Is the particular ordering we’re looking for specific to this set of books, or can it apply to any arbitrary set (as long as none of them are Annoying Books)? $\endgroup$
    – HTM
    May 14, 2019 at 3:39

6 Answers 6


They seem to be ordered

by depth. You need to look at the bottom of the books, the deepest one is on the left.

  • $\begingroup$ It’s not that. You can’t see the depth as they are not pushed to the back of the shelf. $\endgroup$ May 2, 2019 at 12:39
  • 7
    $\begingroup$ What kind of person doesn't push all the books to the back of the shelf and can still have a good night sleep? $\endgroup$ May 2, 2019 at 14:44
  • 6
    $\begingroup$ I try to keep the fronts lined up. Neater that way. Why on earth would I want the books pushed to the back of the shelves? $\endgroup$
    – Gareth McCaughan
    May 4, 2019 at 16:45
  • 5
    $\begingroup$ @MichaelMaggs I have to agree with Gareth here. What civilized creatures don't want their spines aligned? (That goes for books and chiropractic. Bonus!) $\endgroup$
    – Rubio
    May 5, 2019 at 22:21
  • 1
    $\begingroup$ @Rubio Exactly, and since that's not the case here, we can only deduce that this is the answer. Where are my upvotes? :D $\endgroup$ May 5, 2019 at 22:31

I think this is about

the names of the author(s), somehow, and possibly how those interact with the titles,

because when you look at the Annoying Books,

none of them have the author's name on the spine, except for one where the author's surname is also part of the title.


Slatkin, Stringer, Smith, Down & Warrington, Tavris & Aronson, Emanuel & Mannheim, Caplin, Smolin, Woit.

Then this becomes essentially a question:

we need to find out what property of these nine words or word-pairs is being used to order them.

Bearing in mind that one odd-one-out among the Annoying Books, it might be some property of:

the letters of the author's last name which do not appear in the book title.

For the books in the picture, those are:

  1. 4 letters (S, L, A, K)

  2. 1 letter (G)

  3. 0 letters

  4. 3 letters (W, N, G)

  5. 1 letter (V)

  6. 2 letters (U, H)

  7. 1 letter (L)

  8. 2 letters (M, N)

  9. 0 letters

  • 2
    $\begingroup$ This seems like a comment rather than an answer. $\endgroup$
    – Gareth McCaughan
    May 11, 2019 at 21:29
  • 2
    $\begingroup$ (I do agree with what you say, with the proviso that I think the odd one out from the annoying books probably requires closer attention and suggests things are a bit subtler, but it seems to me that that was all already made pretty explicit in OP's hints.) $\endgroup$
    – Gareth McCaughan
    May 11, 2019 at 21:31
  • 2
    $\begingroup$ I try to avoid answers that just say "I think this has something to do with X", especially when the puzzle author has already all but said "this has something to do with X". $\endgroup$
    – Gareth McCaughan
    May 12, 2019 at 19:53
  • 1
    $\begingroup$ Stock text: (... so how does this contribute toward a solution? As this stands, it's Not an Answer, not even a partial one. Having fragmentary thoughts on aspects of a puzzle might be comment-worthy, but you probably want at least a germ of an idea that seems to lead forward before you should post as even a partial answer.) $\endgroup$
    – Rubio
    May 13, 2019 at 4:52
  • 1
    $\begingroup$ Seems to me that #3 and #9 are sufficient grounds to reject the (a priori quite plausible) more specific theory currently advanced here. (I rejected it too for the same reason, along with some others related to lengths that would also explain the eighth Annoying Book but which similarly didn't seem consistent with the available evidence.) $\endgroup$
    – Gareth McCaughan
    May 13, 2019 at 23:53


By Subject, then title


The first is Computer Science. The second is English. The third and fourth are History( then arranged by title: A Law, The History), The fifth is Philosophy. The sixth and seventh are photography (then by title: All, How). The eighth is physics. The ninth is string theory


Mistakes fits my pattern if it is Philosophy, but unfortunately the back cover found in an image on Amazon declares it a Psychology book, and that doesn't fit the pattern.

Possible Correction:

Psychology falls under Medical, so if we categorized it as a Medical book it would lie between History and Photography

  • $\begingroup$ Very good try, but I’m afraid that Mistakes isn’t a history text. $\endgroup$ May 2, 2019 at 13:20
  • $\begingroup$ @MichaelMaggs sorry that categorization was a guess just from the photo, assuming it was a memoir type history. $\endgroup$ May 2, 2019 at 13:28
  • $\begingroup$ Is there a word play on the Mistakes....like someone put it out of order? $\endgroup$ May 2, 2019 at 13:30
  • $\begingroup$ No, there’s no wordplay involved. All books are treated the same. $\endgroup$ May 2, 2019 at 13:36
  • $\begingroup$ Sorry, perhaps I should have been clearer. It’s not subject then title. $\endgroup$ May 2, 2019 at 13:53

Some things that appear not to work

This is in some sense "less than a partial answer". But since this simple-looking puzzle has been here unsolved for so long, even with a bunch of hints, it seems worth doing anything that might help. So, here are some things I've considered that don't appear to lead anywhere useful. (Obviously I'd prefer to post a list of things that do lead somewhere useful. If only there were any.) I might have screwed some of them up, of course. Maybe something here will give someone an idea that leads somewhere. Or maybe something here actually does work and OP will take pity on me and indicate somehow how I goofed.

First of all, some obvious observations.

OP's hints make it very clear that the authors are relevant. Exactly one of the "annoying books" has an author. What's notable about that one? Well, the title is John Buchan and the author is William Buchan. So (1) the title is shorter than the full author name and (2) the author's surname is a substring of the title. (I guess the author is actually related to the subject of the biography, but we've already been told in hints that this sort of external information isn't required.)

So, what might we try? Well, first of all,

OP's hints kinda suggest that we might want to give very close visual scrutiny to the authors' names on the spines of the books. Some sort of steganographic wizardry, perhaps? I've looked closely and haven't found anything obviously interesting, and (though I haven't attempted any sort of serious analysis) it doesn't look as if there's anything magical in e.g. the low bits of the pixel values. In any case, it seems like that wouldn't be fair; this is meant to be an ordering of the books, not randomized books with some sort of ordering then encoded into the picture.

More to the point:

Take the author's name (or just the surname?) as given on the spine, and remove from it all letters found in the title. Hope that we end up with something that yields an obvious ordering. Doesn't seem to work because for the second book on the shelf (Stringer) no letters are left after doing this.


Look for letters shared between author's name and title. Doesn't seem to work because it's hard to see why the Buchan biography would be Annoying in this case, and e.g. the first book has T,I,N (in order of appearance in either title or name) and there's no way that's coming out alphabetically ahead of the second, no matter how we order it. (Well ... sort into order and use reverse lexicographic order; T matches T, N is earlier than S. But then other books later on the shelf are going to come out earlier than that.)


Take the author's name (whole name or surname), index by its length (with or without spaces) into the title (with or without spaces, respectively), either from the start or from the end, and see if we get anything that yields an obvious ordering. Doesn't seem to work because many variants are impossible because either Tavris & Aronson or Emanuel & Mannheim have too-long author names (depending on whether we include spaces and punctuation), and I think I've tried most of the possibilities without finding anything useful. (There are a lot of different possibilities and I certainly haven't been completely exhaustive. Trying out dozens of essentially-identical things in the hope that one of them will turn out to work is Not Fun.)

More far-fetched:

Something to do with words embedded in the authors' names. ("Buchan" doesn't have much, though "ch", "ha", "a", and "an" are all Scrabble-legal and the last two are hard to quibble with.) Doesn't seem to work because "Buchan" does have some embedded words, and no ordering is apparent in the ones found in the authors' names on the shelf; e.g., "smith" is later in the alphabet than anything you can get from "Caplin" if we use only surnames, and if not then "a"/"all"/"ally" are all earlier in the alphabet than anything you can get from "Stringer".


Look for some physical feature of the book spines that somehow picks out particular bits of the authors' names. Doesn't seem to work because for some (Smith, Caplin) there really truly seem to be no such features we can use -- unless, again, there's some steganographic wizardry going on.

  • $\begingroup$ Happy to help close down unfruitful lines of enquiry by confirming that none of those will get you anywhere. No sophisticated analysis or exhaustive search is required. You've understood my hints, but there's some feature in plain sight that nobody has picked up on yet. Now I really must have given it away ... $\endgroup$ May 17, 2019 at 10:37


Alternates between three books with one author and three books with two.

  • $\begingroup$ "Marshall Hall" is part of the title. W S & H is the publisher "Wildy Simmons & Hill Publishing". $\endgroup$ Jun 29, 2019 at 21:09
  • $\begingroup$ It's not that - note the last sentence of hint 3. There's just one rule that covers the whole sequence; it's not a section-by-section arrangement. $\endgroup$ Jun 29, 2019 at 23:05

I think the books are ordered in a


everything is about falling,breaking,mistakes,errors,collapsing,all-in-one, stringtheory, effective python is a random access book. Annoying, Oxford, Camera, Somerset, History (among annoying books they have a synonym or similar name in the title among main picture books.) (their initials read together also gives the answer)

  • $\begingroup$ It’s not a chaotic ordering. There is a specific very simple rule. $\endgroup$ Oct 17, 2019 at 15:34

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