We now encourage some kinds of deep linking to individual sections or pages of Numerical Recipes Electronic (that is, to the electronic edition of Numerical Recipes: The Art of Scientific Computing, Third Edition). You can put live links to specific pages of Numerical Recipes into your web pages, your Adobe PDF or Microsoft Word documents, relevant Wikipedia articles or other reference materials, or anywhere else that has clickable links, subject to the conditions below.
Deep linking is the creation of a link to a specific page within a document or web site, rather than to that web site's main or home page. Without the site owner's permission, deep linking is not always legal (see Wikipedia). Subject to the conditions on this page, we give permission for deep linking.
You can link to any page in our Empanel™ bookreader interface, as long as you clearly identify the link as "Numerical Recipes" or "Numerical Recipes: The Art of Scientific Computing". Those words don't have to be the actual link text, but they must be nearby in the document.
We do not allow deep linking from pages whose principal purpose is to attract page views for advertisements. We do not allow deep linking from pages generated by "content farms" (see Wikipedia definition). We do not allow deep linking from pages themselves consisting principally of links and advertisements. We do not allow deep links from pages that substantially reproduce the Numerical Recipes table of contents. We reserve the right to redirect links from pages that we deem noncompliant to uncomplimentary material that describes those pages as low quality and advertising-related, and to report such pages to content farm filters. We reserve the right to change our deep links policy at any time without notice, including to withdraw permission for any or all deep links.
The Empanel interface allows guest users to view a limited number of pages per month for free, without any registration. If your link references a specific few pages or a specific section, then almost everyone who clicks on it will be able to see the pages for free, likely multiple times, before they use up their free monthly quota.
The URL for a link looks like this:
http://apps.nrbook.com/empanel/index.html?pg=123
(but substitute any page number you want for "123").
In HTML, the code for a link looks like this:
<a href="http://apps.nrbook.com/empanel/index.html?pg=123">Your link text here</a>
which produces a link like this:
Your link text here
If you want to cite a particular section of Numerical Recipes in a relevant Wikipedia article, the citation should look like this:
{{Citation | last1=Press | first1=WH | last2=Teukolsky | first2=SA | last3=Vetterling | first3=WT | last4=Flannery | first4=BP | year=2007 | title=Numerical Recipes: The Art of Scientific Computing | edition=3rd | publisher=Cambridge University Press | publication-place=New York | isbn=978-0-521-88068-8 | chapter=Section 6.2.2. Error Function | chapter-url=http://apps.nrbook.com/empanel/index.html?pg=264}}
which produces Wikipedia text that looks something like this:
Press, WH; Teukolsky, SA; Vetterling, WT; Flannery, BP (2007), "Section 6.2.2. Error function" 
, Numerical Recipes: The Art of Scientific Computing (3rd ed.), New York: Cambridge University Press, ISBN 978-0-521-88068-8
Sorry, definitely no. Our allowing deep links is in no way a grant of permission to use our copyrighted materials other than as is already allowed by copyright law under "fair use" (e.g., quoting short passages of text when properly attributed).
We want people to have limited, but useful, free access to Numerical Recipes Electronic as a ready reference. And, we hope that after using Numerical Recipes in this way, people will want to become subscribers so that they can conveniently access all the book all the time.