Frequently-asked questions

Why are you charging for something that used to be free?

Rember, the only thing that costs money is the complete documentation for NumPy.  This book never existed before (documentation can be a problem even for good free software).  For most people, it is difficult to get motivated to use spare time to write documentation (which can be a tedious task).   Spare time, by definition, is the time you don't have to spend earning money to provide the necessities.  Most of us would rather use spare time to do something fun.  Rather than not have documentation, the idea of charging for it (so that non-spare time could be spent on it) was born.

Free is great.  Who wouldn't turn down something good that's free.  However, because of the fundamental problem of scarcity, everything can't be free.  In other words, it takes effort to produce things.  Money has emerged over millenia as a means to organize the behavior of billions so that other people work to produce the things that we all want.   If you pay for something, you are telling the network of workers that you are serious about your preferences.   Prices emerge from this system of voluntary transactions based on how much people actually value something relative to  the other things they value.   Without these price signals (i.e. if everything were free), then the problem of scarcity would still remain, but now nobody would know what other people honestly value.  We would all have to just guess.   As a result, regardless of our best intentions, it would be easy to end up spending all kinds of time doing things few people actually want or need.  Functioning voluntary markets are essential for prosperity. 

So there is truth to the old adage of "you get what you pay for" in that your money serves as a signal to everybody in the world that this is what you really want people to spend more time doing.   For example, if the NumPy documentation has little value to people then that is an important signal that something must be wrong with NumPy.  Either developers need to spend time fixing the problem, or abandon all but perhaps a little spare time on the project.   Without a price signal, nobody really knows. 

Will a later version of the NumPy software stop being free?

No, No.   Despite the very good reasons for prices to exist in the world, using restricted distribution for open source software won't work because it is then no longer open source.  Charging for the documentation is not some veiled attempt to close the source code and start charging for it.    There will always be a free version of NumPy available as long as people are using it.   The code is open and completely free.  Anybody who wants to can download the code, learn all they desire about how the system works by studying the source code and internal documentation strings.   Additionally, at least a dozen people spread all over the world are involved in the maintenance of NumPy.  It is highly doubtful that any company would want to buy off all of those people in order to convince them to stop working on a free version of NumPy.  Even if a company managed it there would always be others who could take the code and continue.

Isn't your total price too high?

It's possible.  Prices are always a matter of fluctuation --- the old supply and demand notion.   If the price is too high, then the price actually agreed upon in the end will be a signal to others regarding what the current value of NumPy is.  So, it's actually in the best interest of those using NumPy for the price to be high.  This will signal other entrepeneurs to use their non-spare time to make NumPy better.   Relying on the volunteer labor of people will only get you so far (of course there are other indirect ways to fund software development with non-spare time as well).

Isn't your per-copy price too high?

Maybe.  If you have a specific offer, email me and let me know your offer.  Again, time will tell.  Prices are a trial-and-error process.  For some people the price will be too high.  Others will be willing to pay it in order to acquire something of value.  A price system lets those who value something the most receive it.

Is your license saying that if I buy the electronic copy only one person can ever look at it?

No, of course somebody can look over your shoulder at your copy.  You could even send it to them for a trial read, or copy portions under "fair-use."    The point is that if somebody needs to use the book regularly, then they should buy their own copy.   You should not just copy your book for them (electronically or otherwise).

Is there something like a site-license so that everybody in our organization can access the documentation?

If you buy 20 copies of the book then you can share it with anyone in your local organization (site-license). You will also receive the html version when it is ready that can be posted on an internal-only webserver that is not visible from outside your institution (out of the glare of Google).   Honestly, though, if your institution is using Python for scientific and technical computing, it is in your best interest to purchase as many copies of the documentation as you can to encourage its further development. 

Will there ever be a bound book that I can buy?

Yes. Details forthcoming. Those who have purchased the e-book will be able to buy the bound book at cost.

Doesn't requiring payment for documentation "shoot-yourself in the foot."

From time to time, some complain that because the documentation is (temporarily) non-free then people won't download it and use it. First of all, there is all kinds of "free" documentation. Just as much or more than Numeric in fact. Look at http://www.scipy.org for examples and in the source itself (there is a doc directory). Second of all, the book goes beyond "documentation" and so is better considered as a book describing NumPy. People may continue to use Numeric and Numarray but the developers are not. It will be harder and harder to get help as the standard answer will be "use NumPy." Time will tell, of course.