There are a lot of books out there about learning new languages or software related technologies. The problem is that almost all of them assume that you know something about the field already; or are at least hard-core enough that you can survive being thrown in at the deep end -- the equivalent of the kids of 20-odd years ago who started out by self-teaching assembler on a BBC micro or Z80 -- and can take being started out on ODBC related code (I'm looking at you, Dive into Python.)
Hello World! is one of the rare exceptions, a gentle, and humorous introduction to the idea of programming, using Python, a language well suited to filling the niche that BASIC dialects did a generation ago. Even to a crusty and cynical old-timer, like myself, it makes entertaining reading -- not only is the writing style light and engaging, but you can nod sagely and think "Been there, done that" at all the "In the good old days" asides.
That said, it's not a book aimed at teaching people in my position, so I showed it to some members of the target demographic.
My wife, who has programmed a mean Excel spreadsheet in her time, but never anything in the way of more procedural languages, has enjoyed reading it and trying the examples (even if composing Python code using dictation software is a truly painful exercise); which is tribute to its style. While the examples may be rather trivial, in the wider sense, the immediate sense of achievement they bring help motivate and reinforce the reader.
I also showed the book to a teenager who had wanted to learn programming over the school holidays, and to whom I'd earlier loaned a copy of the O'Reilly Learning Python. She liked Hello World! very much for its very approachable style, and tells me that (to me, unsurprisingly) it gave her a better understanding of the real basics than the more advanced text has done.
However, as she also perceptively pointed out to me, "while it is very good at giving a budding programmer the groundings you'd definitely have to move on to a different book to get the more complicated bits."
It is strictly an introduction or 'taster' sort of book, a teaching aid rather than a reference. If the coding bug bites, then you will want to move onto something else to get a broader and deeper understanding, beyond the introductory simplifications (such as Hello World!'s simplifying use of old-style objects)
Looking at it as an old-timer, it is clear that the book is intended to be a whistle-stop tour of the idea of coding, and getting the computer to respond to what you have done. There isn't a sense of structured incremental development in the way material is presented, more one of getting the user to the "Ooh! Shiny!" quickly. That makes sense in terms of seeing if the coding bug bites before possibly dampening enthusiasm with comparatively boring, if worthy, things like operations on strings (split, join, search), which are left until late on. Unfortunately, one of the topics deemed too boring to mention was testing -- even though Python comes with a unit test library in the "batteries included", the idea of "how do you know if what you've written works?" wasn't raised.
The book comes with the expected accompanying download bundle : Python 2.5, and all the source and tools mentioned in the book. My wife had a little trouble with getting some of the tools to work -- the Stani's Python Editor program as supplied didn't appear when invoked from the start menu, and, when started from a command line, complained at not being able to find wxPython; although when I installed the latest wxPython for Python 2.5, the install process detected a prior version being present -- so it would help to have someone around who is confident with managing the computer being used.
Overall: definitely a good book for the absolute beginner, and I'd rate it a very solid four stars out of five. The reason I mark it down is that while it's great for teaching as it's laid out, it's less good as a reference afterwards.