Here are some interesting books from the Microsoft Press Store about C#, SQL and Dynamics AX.
Coding Faster: Getting More Productive with Microsoft Visual Studio
https://www.microsoftpressstore.com/store/coding-faster-getting-more-productive-with-microsoft-9780735649927
CLR via C#, 4th Edition
https://www.microsoftpressstore.com/store/clr-via-c-sharp-9780735667457
Adaptive Code via C#: Agile coding with design