We're a heavy user of AWS at work; in fact, someone once described Amazon as "a cloud provider with a bookstore on the side". As such it's inevitable that you get a view of some services and just enough knowledge to get by, but without a real understanding of the bigger picture. I hesitated to buy a book, because it could become obsolete so quickly, but from the table of contents this looked like it covered the fundamentals, which aren't shifting so rapidly.
The book is a decent attempt at providing the bigger picture, though it quickly becomes clear that the picture is big and disparate; CloudFormation looks like a jumble, because it is, as it is a way of creating so many different types of resource. I'm not going to suggest this book will make anyone an expert on IAM, VPCs and ELBs, but it puts enough body on the bones of the alphabet soup. Much of the book focuses on EC2 and S3, which are indeed the services I'm most familiar with, but it also clarifies EBS and dips into topic such as RDS and SQS. There's a chapter on DynamoDB, which is in fact a weak spot in the book: the query APIs aren't very well explained and it just looks like gibberish - I suspect it's a big enough subject that would deserve a book to itself. Amazon is adding continuously to the available services, and there are some that aren't covered at all, but it's a good grounding in the technology.