The amount of books related to event processing is growing, and in the next year or so there will be several books added to the already existing one, looking at event processing from different angles.
First let's review the existing books.
"The power of Events" by David Luckham was the pioneering book in this area and became an icon by its own right, the book was published in 2002, and influenced the thinking in this area, including the name coined "complex event processing" that is in use as a name being used for various products in this area.
The book "Distributed Event-Based Systems" by three members of the research community: Gero Mühl, Ludger Fiege, and Peter Pietzuch. It should be noted that the "DEBS" community which concentrated around pub/sub and distributed middleware, has joined forces with the community that deal with event processing languages, architectures and execution models to form the event processing community.
This book published in 2006 deals mostly with the infrastructure that enables event-based interaction (such as: pub/sub) and is a good textbook on the infrastructure topics.
The book "Event-Driven Architecture - how SOA enables the Real-Time Enterprise" is a new book by Hugh Taylor, Angela Yochem, Les Phillips, and Frank Martinez available also as a Kindle book. I have not read it yet, but from the title it seems to look at EDA as a SOA pattern. Will add it to my next periodic Amazon order.
Now - to future books. Amazon also shows a book that has not been released yet, by Sharma Chakravarty one of the veterans of active databases and Qingchun Jiang. The book is entitled: "Stream Data Processing: A Quality of Service Perspective", and has "Complex Event Processing" is its sub-title, seems to be a monograph about Sharma's approach to unify stream and complex event processing that he presented in the DEBS 2008.
Annika Hinze and Alex Buchmann, again, two persons from the academia, well known in the community. Their intended book is a collection of articles, entitled: "Handbook of Research on Advanced Distributed Event-Based Systems, Publish/Subscribe and Message Filtering Technologies", and is geared towards the research community. I don't know the schedule.
Another forthcoming book by well known figures in our community: Roy Schulte and Mani Chandy is entitled: "Event Processing: Designing IT Systems for Agile Companies".
This book will provide business oriented view of event processing and its relations with various part of the enterprise architecture (SOA, BPM, BI).
Last but not least, the book that Peter Niblett and myself are writing entitles "Event Processing in Action", the book focuses on the building blocks of constructing event processing applications, and provides a deep dive of application building using a use case.
The fact that various publishers have taken the investment in event processing oriented book is an indication of the interest in this area. Enriching the community with several books with different viewpoints and focus area will help in both the understanding and teaching event processing concepts and facilities.