There are quite a few people who have realised that smartphones, tablets and e-book readers are a great way to store and read technical manuals. It's not just that these books are not taking up room on the desk. It's also the fact that they're on hand when you need to refer to them and easy to get stuck into when you find yourself with an hour spare and realise you could spend a little time learning something useful.

In the tech world, some of the most useful books available are from the O'Reilly collection. So, what could be better for your ebook collection than getting some of these great O'Reilly ebooks for free? Not a lot, really.

Today we've decided to showcase a few of the best O'Reilly ebooks you can pick up for free. Many of these free ebooks are out of print and offered online specifically to keep the works accessible to you all, so you don't need to feel bad about getting it for free. And if you do feel bad, just go buy a new O'Reilly book to keep the money going towards more of these projects. Note that some of these are available in ePub or PDF formats, while others are only available as HTML.

Linux Network Administrator's Guide

Olaf Kirch & Terry Dawson, ISBN 1565924002

This book explains all the basic software and protocols you need to understand in order to begin network administration under Linux. It also talks a little about hardware needs. It doesn't focus on Samba as there's another free O'Reilly eBook dedicated to Samba.

Readers of this book may also appreciate Linux Device Drivers and Learning Debian GNU/Linux, which are also available to read for free.

Producing Open Source Software

Karl Fogel, ISBN 0596007590

This is a book to guide readers through the process of creating open source software. Primarily, it's for the developers and managers of the open source project, but it's also useful information for people who plan to participate in open source projects. Essentially, it discusses the human side of the process and how to make your project succeed.

Creating Applications With Mozilla

David Boswell, ISBN 0596000529

You may have heard of a number of excellent Mozilla-based projects, such as Songbird, the Flickr Uploader and Postbox. If you want to create a Mozilla application or work on one of the established applications, then this book is a great place to start.

CouchDB: The Definitive Guide

J. Chris Anderson, Noah Slater, Jan Lehnardt, ISBN 0596155891

CouchDB is perfect for creators of web applications that need a reliable, scalable, fast database manager. Written by three of the creators of CouchDB, this book is intended to be all you need to know about the document-oriented database.

We The Media: Grassroots Journalism by the People, for the People

Dan Gillmor, ISBN 0596102275

We The Media is something a little lighter for anyone who's interested in citizen journalism, either as a movement or as a new participant. If you want a glimpse into how online journalism will change journalism as a whole forever, this book will deliver.

Don't forget that O'Reilly have a current list of their open books here. Which O'Reilly eBooks are your favourites?  If they are online, let us know the links to them so we can check them out.