Pathfinder - are the books required?

[Hytheter]

Ok so as a DnD 3.5 player I've started looking at Pathfinder using the PRD and I have to say it certainly looks interesting.
But what I've noticed is that whereas the d20srd has at least few semi-important details omitted, the PRD seems to have everything you need to know. This strikes me as convenient as a player, but unsound from a business stand point.

So is there anything I'm missing? Or do you not really need the relevant books to play Pathfinder so long as you have the PRD?

[Bhaakon]

No the books are not required to play Pathfinder, since, as you point out, everything mechanical is available on the internet. What's not available for free are the setting and modules, which remain proprietary.

You only need the books if you plan on playing in Pathfinder Society, Paizo's organized play society. They check to make sure that you own any source books you use in making your character.

As for the why of it, Pathfinder mechanics are largely lifted from 3.5 material under the Open Gaming License (OGL). They did this because it gave them a built-in existing fanbase (all the people who were used to playing 3.5 and didn't like 4). But it also meant that all their game mechanics also had to be OGL, and therefore free.

As to whether this is a good model, I actually think it is. The only way to have a successful RPG is to get a lot of people playing it, and giving it away for free certainly accomplishes that goal. Then they make all their money off the modules, setting books, adventure paths, and other paraphernalia (plus all the people who want actual books to use). It also sidesteps the issue of piracy, to a certain extent.

Many industries use a similar model. Printer companies sell printers at a loss and ink at a huge markup, console companies sell consoles at a cost or less and games at a profit, there are many free games with incremental purchase add-ons, etc. As long as you can guarantee a large captive user base, you can find ways to make money off them.

[Hruken]

I don't use the books. But my table is okay with having laptops out, so it works for me. Some like the feel of having the books, and some tables are not okay with laptops, so for that it comes down to personal preference.

It also helps that we play homebrew campaigns, so very little of the setting comes up.

[TheIronGolem]

Ok so as a DnD 3.5 player I've started looking at Pathfinder using the PRD and I have to say it certainly looks interesting.
But what I've noticed is that whereas the d20srd has at least few semi-important details omitted, the PRD seems to have everything you need to know. This strikes me as convenient as a player, but unsound from a business stand point.

So is there anything I'm missing? Or do you not really need the relevant books to play Pathfinder so long as you have the PRD?

Books are convenient, but optional. I ran a PF campaign for more than a year, as the sole owner of any of the books, and said books didn't even get cracked open on more than a handful of occasions.

As for the business view, it's not as unsound as you might think. Anyone who wants to play a tabletop RPG for free will be able to do so with minimal effort. Paizo presumably sees no point in standing in the way, and would rather be known for helping fans out than for making trouble for them (like TSR became infamous for doing in the 90's). The evidence suggests that's working just fine for them so far.