Recently I have been reading the Sharepoint 2010 Developers Reference from Microsoft, written by Paolo Pialorsi.
I have about 12 months experience of developing with Sharepoint 2010 and therefore have a good understanding of the product and developing solutions for it, however, it has been some time since I did anything in anger and I needed a good reference to assist me when my experience was not enough or if I needed to brush up on some topics. I also wanted to be able to deep dive into some areas of Sharepoint I had not touched before.
The books starts very well, even for less experienced developers, by giving a good overview of the Sharepoint object model and some of the more basic concepts, which was fantastic to re-familiarise myself with some of the key points and even pick up a few bits of information I never knew.
The book then goes on to cover most of the major areas concerned with Sharepoint development such as web parts, both basic and advanced, customising the user interface, workflow and document management. The book even covers more complex areas that other books don't always cover such as programming the powerful in built search engine.
On the whole this book has been an excellent resource for me whilst working with Sharepoint and I would highly recommend even the most experienced developers grabbing a copy to use it for what the name suggests, a reference, and it performs this task extremely well.
In summary, this is a very comprehensive overview of development with Sharepoint 2010, however, even a book of this size can never dive deep enough in order to cover all of the technical aspects of a product as broad and complex as Sharepoint 2010. To be honest though, I have only had to open another book a couple of times with this book sufficing for virtually everything I needed in combination with the internet of course.