“Bookend the Future” is the title of the tenth chapter in the book Decisive by the Heath brothers.

This is the writer's explanation of the concept:

Penstock uses a method he calls “bookending,” which involves estimating two different scenarios: a dire scenario (the lower bookend), where things go badly for a company, and a rosy scenario (the upper bookend), where the company gets a lot of breaks.

Although I fully understand the concept, I couldn't define a meaning for the word “bookend” and put it into words so I can recall it easily.

According to the Oxford online dictionary,

Bookend: as a verb means “to be positioned at the end or on either side of (something).”

But I think that this definition doesn’t apply here.

As far as I understand it, this concept is a kind of guesstimation.

I want to know what a native speaker would understand by the phrase “bookend the future”. (I don’t want to have to recall the whole concept every time to interpret the phrase.)

Can you help me with a simple definition for the phrase “bookend the future”?

3 Answers 3


The verb bookend derives from the noun. Bookends come in pairs:

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So bookends act like brackets. The writer invites to you "bookend" your predictions for the future by imagining a best case and a worst case for your company; the actual outcome will lie somewhere between these.

  • So you suggest that I can Define "bookend the future" as my prediction for the future but with a process or a little logic as we define our best & worst case so we can hit in between so we reduce the fallacy . as you suggest can i translate bookend the future as " guesstimate the future" ?
    – Corabict
    Commented Nov 27, 2013 at 15:00
  • 1
    @Corabict “Bookend” as a verb basically just means “place some things on either side of (something else)”. Penstock came up with the phrase “bookend the future” to describe his method, which consists of imagining a best plausible future, then imagining a worst plausible future, then using these two possible outcomes as metaphorical bookends (really just lateral boundaries) between which to consider the current price of the company’s stock. Commented Nov 27, 2013 at 15:05
  • 2
    @Corabict It's the opposite of estimating a future result: it's determining plausible limits within which the future result is likely to lie. Commented Nov 27, 2013 at 21:45

The writer is making up his own definition for the word: You quote his definition. So you wouldn't expect this to be the normal definition or a widely-recognized definition. He's just told you that he's making it up.

It's fairly routine for a writer on a specialized or technical subject to make up his own definition for a word for the purposes of this one article or book. If you are writing something and you find that you are repeatedly saying, for example, "machines that use either petroleum products or steam as their source of power and which produce electricity but where the purpose of the machine is not to produce electricity but to perform some other function", it makes a lot of sense to replace twenty such repetitions of this phrase with one word, and then at the beginning of the article say, "in this article I will talk about machines that etc etc. For convenience I will refer to all such machines as cogenerators", ie, make up a suitable word. This eliminates a lot of repetition, which makes it easier for the writer and easier for the reader. Not to mention sparing the reader from having to figure out that each time you use this phrase you are, indeed, using exactly the same phrase. Or worse, you say the same thing in different ways each time, and now the reader is not sure if you mean the same thing or something different.

The only question that remains, then, is how closely his definition resembles the conventional definition. You quote a dictionary definition. That conventional definition describes "bookending" in terms of positioning things on either end of something. The writer's special definition talks about putting an upper and lower limit on outcomes, i.e. put limits on either end of something. So it's pretty consistent with the conventional definition.

  • yes after further consideration it's consistent with conventional definition so the future lies between two scenarios, like the books between two brackets [bookend] & it's a pretty good depiction thanks for your help
    – Corabict
    Commented Nov 27, 2013 at 17:08
  • Be that as it may, this answer holds very well. "Bookend" is not a very suitable metaphor for the upper and lower limits in a spectrum that is numeric, or from good to bad, or whatever. It's better suited for physical location, in time, space, or a signal (speech, writing). For instance, "the show was bookended by two news reports" (a news report came before, and another one after). Bookends do not indicate a lower and upper bound; only two tight physical boundaries that are equivalent.
    – Kaz
    Commented Nov 28, 2013 at 2:48
  • Kaz: I guess that's just where people's intuitive ideas about the meaning of a word can differ and temper the effectiveness of a metaphor. This example makes good sense to me: there's a lower bound, the left bookend; the upper bound, the right bookend; and then all the actual possible outcomes are the books in the middle. (I tend to think of values ascending from left to right so I think of the left bookend as the lower bound.) If your intuition doesn't picture it like that, then I guess the metaphor is less effective for you.
    – Jay
    Commented Dec 2, 2013 at 18:37
  • ... I think of it like a number line. Say the lower and upper bounds are 10 and 15. Then there's 10 .. 11 .. 12 .. 13 .. 14 .. 15. 10 and 15 are the bookends, 11 through 14 are in the middle.
    – Jay
    Commented Dec 2, 2013 at 18:39

There is a better term than "bookend", "bracket", as in artillery fire:

a method of adjusting fire in which a bracket is established by obtaining an OVER and a SHORT along the spotting line and then successively splitting this bracket until a target HIT or desired bracket is obtained.

Source: FM 6-40 Glossary

"bracket the future" is better because a bookend is a static device to stabilize books, but bracketing is a practical exercise to discover a setting for your howitzer to hit a distant target, but one that is within range, and within spotter intel. OVER and SHORT correspond to test shots, the spotter radios (feedback) the firing crew whether the last shot went over or was short of the target. Azimuth is adjusted accordingly.

Time is likened to distance in the simile.

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