Summer is a great time to catch up with books that you have on your shelf, but do not have time to read. Obviously I would suggest starting from my recently released "Expert Delphi", but there are plenty of other interesting books to look at. I have recently bought printed (!) version of "Serverless Architectures on AWS" book by Peter Sbarski.
"Serverless" is to me the biggest thing in years on the "server-side". No more thinking in terms of provisioning virtual machines in the cloud. The very heart of this new capabilities is the Amazon Lambda service, where you can just execute a function in the cloud. That's granularity and cost efficiency! The second key service is the Amazon API Gateway, which is a kind of a backbone for any API you want to publish. It provides API versioning, optional throttling and other nice features.
The "Serverless Architectures on AWS" also provides deep insights into practical security aspects of API publishing, that is probably the most important factor in successful "serverless" implementations. Now, to the next chapter;-)