Bluetooth is a standard for wireless integration of small devices. "Bluetooth for Java" is specifically about using Java to program Bluetooth-enabled devices. The specification for Java and Bluetooth was released in February. However, vendors are implementing the specification now and most won't be ready/available until Fall 2002.
Bluetooth is a technology for wireless communication. It is similar in functionality to the way laptops connect to the Internet from home/office, but is typically used for short burst communications instead of a continuous connection. Because of this difference, Bluetooth is more typically found supported in wireless phones and personal devices.
What "Bluetooth for Java" offers is not an overview of what Bluetooth is. Instead, Bruce Hopkins and Ranjith Antony describe how to develop wireless Java applications using Bluetooth for a variety of platforms. This includes an API overview of the Java library, development of Bluetooth-based services, highlights of security concerns, and walkthroughs for development with some of the different tools available. Programs will not be just J2ME (micro devices) based, but will also be for J2SE (client/desktop).