This tutorial series, led by Nexmo developer advocate Tomomi Imura, covers how to add programmable SMS capabilities to Node.js applications using Express, including sending, receiving, and verifying SMS messages, as well as implementing two-factor authentication for iOS apps. To complete the tutorials, developers need a Vonage API account with an API key and secret, and a virtual phone number. The series includes code samples and instructions on how to use Nexmo's SMS API to build secure messaging systems.