Stephan leads the product infrastructure engineering team at Gusto. Gusto has quite a bit of Ruby on Rails in the software behind their offerings and provides the perfect ground for the analysis of complex applications due to "Payroll" being both a deep and very wide domain. And Gusto is a lot more than payroll.
Stephan is the author of Component-based Rails Applications in which he lays out the previous iteration of Ruby and Rails modularization based on gems and engines. He is currently working on a new book called Gradual Modularization for Ruby and Rails, which improves on his previous ideas by reducing the cost of the needed work and increasing the opportunities for benefiting from it.
Find out more about Stephan at stephanhagemann.com.