If you want to learn about Google Wave then check out the book The Complete Guide to Google Wave written by Gina Trapani with Adam Pash.
This book’s contents are freely available to view online. Here is what is covered in the book:
Chapter 1 Meet Google Wave
Find out what Google Wave is and what problems it solves.
Chapter 2 Get Started with Wave
Set up your Wave account and create your first wave.
Chapter 3 Manage Your Wave Contacts
Find and add people and groups to collaborate with in Wave.
Chapter 4 Find and Organize Waves
Tag, file, search, and filter waves.
Chapter 5 Dive Deeper into Wave
Add rich content to your waves like maps and photo slide shows.
Chapter 6 Master Wave’s Interface
Navigate Wave from the keyboard and customize your Wave interface.
Chapter 7 Wave Gadgets
Add interactive content to your waves with gadgets.
Chapter 8 Wave Bots
Automatically update the contents of your waves with bots.
Appendix A What Wave Can’t Do
It’s not just you. See what’s NOT working in the current version of Wave, and what features the Wave team has promised are coming.
Appendix B Contribute to The Complete Guide to Google Wave
In the spirit of Google Wave, this guide is a collaborative effort. We need you (yes, you) to help revise and expand this guide as Wave evolves.
You can start reading this book here: http://completewaveguide.com/
The preview edition of The Complete Guide to Google Wave will be available for purchase as a DRM-free PDF in November of 2009. The first edition will debut in January as both a PDF and a softcover print book, with new editions to follow throughout 2010.