user3059: There have been quite a few book-recommendation/reference-request questions lately. Some of them have been closed and even deleted while others have remained open. 
I'm curious on what the site policy is, and I'd like to limit this discussion to 

whether all textbook/reference recommendation questions, or a subset
  of them, are too broad/open-ended for the site

(it's possible that some were closed and deleted as duplicates, although I will probably post another question on meta about deletion policy).
To start the discussion, here are two questions that motivated this meta post:

Introductory biology text for an outsider [open]
https://biology.stackexchange.com/questions/35335/reference-request-regarding-biomathematics-theoretical-biology [now closed]

In particular, I'm curious why [1] is open and [2] is closed, as [1] is arguably more general than [2].

user6307: I can appreciate that we would be a good resource for textbook recommendations, but there has to be countless questions here asking for introductory biology text books which are all essentially duplicates. The more focused recommendation questions (ie those with ample background and specific fields) are slightly more tolerable. Slightly. I feel like the former should be closed while the latter answered. Unfortunately, applying such a rule on a case-by-case basis would seem largely arbitrary (as you observed by one question be closed and the other open) and likely lead to arguments. Additionally, there are many other book review sites on the internet (eg Amazon) which any motivated person could find and use. For these reasons, I almost think we should have one textbook recommendation question with a community wiki answer where people can add books recommendations for specific topics/fields. Any subsequent question can be closed as a duplicate. 
I think a similar idea could also be applied to the evolutionary "why" questions (eg why do we have two hands?, why don't we have two hearts?). These questions all have the same answer: there is no why or it's impossible to know why. A brief explanation of the basics of evolution is all that is required and all such questions could be closed as duplicates. 
I'm not entirely sold on the idea, but it's there for discussion

3059: <p>There have been quite a few <a href="https://biology.stackexchange.com/questions/tagged/book-recommendation" class="post-tag" title="show questions tagged &#39;book-recommendation&#39;" rel="tag">book-recommendation</a>/<a href="https://biology.stackexchange.com/questions/tagged/reference-request" class="post-tag" title="show questions tagged &#39;reference-request&#39;" rel="tag">reference-request</a> questions lately. Some of them have been closed and even deleted while others have remained open. </p>

<p>I'm curious on what the site policy is, and I'd like to limit this discussion to </p>

<blockquote>
  <p>whether all textbook/reference recommendation questions, or a subset
  of them, are too broad/open-ended for the site</p>
</blockquote>

<p>(it's possible that some were closed and deleted as duplicates, although I will probably post another question on meta about deletion policy).</p>

<p>To start the discussion, here are two questions that motivated this meta post:</p>

<ol>
<li><a href="https://biology.stackexchange.com/questions/10376/introductory-biology-text-for-an-outsider">Introductory biology text for an outsider</a> [open]</li>
<li><a href="https://biology.stackexchange.com/questions/35335/reference-request-regarding-biomathematics-theoretical-biology">https://biology.stackexchange.com/questions/35335/reference-request-regarding-biomathematics-theoretical-biology</a> [now closed]</li>
</ol>

<p>In particular, I'm curious why [1] is open and [2] is closed, as [1] is arguably more general than [2].</p>
 6307: <p>I can appreciate that we would be a good resource for textbook recommendations, but there has to be countless questions here asking for introductory biology text books which are all essentially duplicates. The more focused recommendation questions (ie those with ample background and specific fields) are slightly more tolerable. Slightly. I feel like the former should be closed while the latter answered. Unfortunately, applying such a rule on a case-by-case basis would seem largely arbitrary (as you observed by one question be closed and the other open) and likely lead to arguments. Additionally, there are many other book review sites on the internet (eg Amazon) which any motivated person could find and use. For these reasons, I almost think we should have one textbook recommendation question with a community wiki answer where people can add books recommendations for specific topics/fields. Any subsequent question can be closed as a duplicate. </p>

<p>I think a similar idea could also be applied to the evolutionary "why" questions (eg why do we have two hands?, why don't we have two hearts?). These questions all have the same answer: there is no why or it's impossible to know why. A brief explanation of the basics of evolution is all that is required and all such questions could be closed as duplicates. </p>

<p>I'm not entirely sold on the idea, but it's there for discussion</p>
