These two Excel Services books are out (or will very soon be). I decided to use this space to shamelessly promote them! :)

The first book is called "Beginning Excel Services" and is written by Liviu, Eran and Craig. I have been working with Liviu for about 8 years now and with Eran for close to 12 years. I have worked with Craig for about 3-4 years on Excel Services. All three are incredibly professional and this book should be the corner-stone for anybody wanting to deploy Excel Services. As a bonus, this book will probably become a collectors item in the next few years as this is the only known picture of Liviu (left-most in the picture) where he's actually smiling.

Beginning Excel Services explains what Excel Services is, what are the benefits and how to get started. The book starts from the basics, and shows you how to deploy an evaluation copy of Excel Services. It then goes into various aspects of the architecture, performance and capacity planning, security and protecting the information, deployment and administration, and bringing in external data into worksheets. The last part of the book has detailed step by step chapters that guide you through each scenario. These include publishing workbooks to the server, controlling the distribution of workbooks, reporting, interacting with data and business intelligence.

The second book ("Professional Excel Services") is by yours truely (yes, that's my ugly mug on the cover - I told Wrox that having my picture on the cover will hurt sales, but they didnt listen),

Professional Excel Services is all about the Excel Services developer – the first part will explain all about the internals of Excel Services, will go through all the programming options that Excel Services provides. This includes detailed information about UDFs and Excel Web Services, but it also contains information about common “gotchas” and about the reasoning behind some of the features. The second part goes through a dozen or so examples showing various solutions that can be done by using Excel Services – most of them reusable and generic enough that they can be used in almost any solution. Through these examples, the book shows how to use not only Excel Services UDFs and Excel Web Services, but also AJAX, SharePoint, Workflow and Excel Client technologies.