Hey John! Thanks for posting. Let me answer these:
Does your book serve as a tutorial or a documentation for Prototype & Scriptaculous?
It is sort of halfway between the two worlds. The book features
comprehensive coverage of both libraries in their most recent versions (Prototype 1.6, script.aculo.us 1.8), with absolutely nothing left out. In this respect, it is very much a documentation.
On the other hand, I strove to make it
not feel like a reference API documentation, and more like a tutorial, with long-running examples, concrete usage samples, and a ton of best-practice advice. As it does not require any prior knowledge of the libraries, it can serve as a tutorial, but will usually wade deeper into details than a tutorial would.
Do you show snippets of code? or you built a complete project?
Because of this dual nature I just explained, I do both. I show a lot of code snippets (sometimes long ones) when going through the API contents, but also build quite a number of more intricate examples and mini-projects, especially when going Ajax or exxplaining the DOM capabilities.
What are the technologies you used for the server-side?
I went on a limb and used Ruby.
Not Rails: pure Ruby. I understand that this can put people off, but I went this way because I did not want the book to require a server setup from the user. Although some server-side technologies are quite trivial to setup (say, EasyPHP on Windows), they can be more complex and involved in most cases (on Linux, or going JavaEE or ASP.NET).
The thing with Ruby was that you just needed to install Ruby (which is straightforward on all platforms, the appendices detail how), and then
your whole server environment is just one small Ruby script. Fortunately, Ruby is so readable it makes sense even to non-Rubyists; and when examples used more powerful syntax, I explained it.
The great thing about this choice is this:
you don't need any server setup to run an example, however advanced; you just need to run the Ruby script!
I have to say that a 448 pages covering these two libraries seem to be delicious and informative.
That's what I think, too :-)