A common question among all members who use and employ the Drupal CMS for their www needs, is "Does Drupal scales"? And if the answer is affirmative, "How does it scale?"
A team of three Drupal Experts from the Tag1 Consulting (Jeff Sheltren, Narayan Newton & Nathaniel Catchpole) tries with their book -and I dare to say- with great success to deal with that unresolved for many issue. Of course, by just writing a book with performance tips and techniques is not possible to cover every different aspect or solve them in an optimal way. But that is not theirs goal. Their primary goal is to make every Drupal developer / site builder / administrator fully aware of the common Drupal problems the community is already facing and which practices exist that may help in their fights for a better Drupal.
However, the true goal of the book is to make Drupal people understand the fact that optimising a Drupal application and taking care of its performance, is an ongoing process that must be start before the delivery. In many situations, it is a process that follows the launch for weeks or even months. Keep in mind, that there are best practices for specific needs. What works in one case, may completely fail in another. Why? Due to the completely different context. Every Drupal installation is unique. Thus the first chapter of the book is the "Measuring and Analysing Website Performance". The writers help us to discover and decide what really matters for us, which parts must be improved and last by not least, how to specify our measurable goals.
Having the goals written in our hands, we can decide if what Drupal offers out of the box helps us or not (Chapter 3, Drupal Performance), which Database is for our application (Chapters 13, 14, 15) or even if we should consider a CDN or a Reverse Proxy (Chapter 19, Reverse Proxies and Content Delivery Networks) to better improve our user's experience.
But someone would say that all the above will eventually help starters with their initial needs. What about the "big players" with multiple servers and some million records available on their databases? Don't worry, there are chapters for us too. What caught my attention was the continuous integration deployment technique with Jenkins CI (Chapter 9, DevOps) and a working Varnish configuration example full of really useful comments (Chapter 19, page 200). You can take a look of the full table of the contents in the O' Reilly page.
In a nutshell, the book stands out by itself. Although it was released in October 2013 (a month ago), the vast majority of its chapters deal with current hot performance topics. The writers not only are leveraging bleeding edge technologies, but they prove that Drupal already support them. My opinion is that you shouldn't consider it as a "plug-n-play" book, although it provides working configurations. I believe it's more a companion book for all of our ongoing and future projects, full of rich tips that may work and help us, maybe not. It is up to us.
PS. The answer is "Yes, Drupal can scale!"