For those who think Microsoft is on the ropes (O'Reilly on book trends)

Looks interesting, but one must not forget the meaning of 'relative'. If 100 books on Ruby were sold last year, and now 300, that's 300% growth, while Java and C/C++ have had so much written on the subject, that a 15% decline is a drop in the ocean.

You get the idea ;)

Great post Matt! I agree that OSS is growing at the expense of EBM (everyone by microsoft).

Re. Java slowing down while PHP et al grow: I think that the application domain is critical to understand this trend.

PHP is growing for sure, and it's growing well beyond what the book sales figures say because you don't need a book to learn php, there are thousands of sites that will teach you enough to get something fairly easy done with PHP (and LAMP/WAMP). This can't really be said for Java. You need a different type of skill to be a Java developer. Generalizing, I'd say that a Java developer can become a PHP developer, but the reverse is not always that easy.

So, while you (and we) see Java interest strong in the enterprise domain, there is a lot of interest at the individual developer level about PHP. PHP use in the enterprise is growing also, but it's nowhere close to where Java's penetration is, nor the penetration of PHP in the non-enterprise domain.

Really weak study.
A much more serious one would be, for example, how many software packages are been developed in any language. For example using a linux box and doing statistics with apt/yum it comes out that Perl and Python outake any other language at hand. That's the most trustable source since it reflect not the number of people using the language, but the number of SUCCESFULL projects. (I wonder how many people has succeded to do anything usefull with javascript).

Job search web sites are also trustable (what people with the money want to pay for). In this case Java outpaces anything in planet (it makes sense since it's the standard in bank and telcos, wich employs many people).

But rating a language on books solds is just untrustable. For example I doubt many Python or Java or Postgresql books could be sold since anything is available for free on the web (tutorials, API references, libraries for database access, networking, ... and even Flash animations explaining the technology used). It could even be considered that people buying books are out of sync with the "internet". (I doubt buying 10 SQL books will allow you to do a 1% of what you can do reading a "post" on the net about Postgresql+R integration).

I have to use Java day in, day out but I have no need to buy any book. Why? Because everything is free and well documented on the web:
http://java.sun.com/j2se/1.5.0/docs/
http://www.oracle.com/technology/products/ias/toplink/jpa/resources/toplink-jpa-annotations.html
http://java.sun.com/j2ee/1.4/docs/api/index.html
http://java.sun.com/j2se/1.4.2/docs/api/index.html
...

I agree totally. The number of books sold for a specific technology is clearly connected to the quality of the free offerings.

There are times when I personally suspect that the increased book sales for Ruby is a product of genuine interest in Rails, meager documentation and a community where the core developers mainly speaks Japanese.

Interesting, though of course only shows the demand for books.
e.g. DB2 is still a major player in databases, though hardly shows here. Perhaps it's because DB2 is more used on large systems and in large enterprises, where formal training and online manuals seem more appropriate than a couple of books.

I've been working on a large Java project (650,000+ lines of code) for quite a few years now. We haven't bought a Java book in that time. We're all experienced and proficient in Java and when we do need to find something, we pop out on the net real quick and find the info.

Too, for anyone who's programmed in Java for a while has probably experienced, new features just means there's another API to glance over and then start using it. It isn't like other languages with a giant hodge podge of function calls. Anytime I do anything new in other languages, I "need" a user's guide or book to get me going. Most of the time in Java, the reference guide that comes with it is enough.

FYI, a couple month's ago, we had to do a little add-in to Outlook and did it in C#. We did buy a book for that project so we probably contributed to the skewed looking book sales results ;-)