Trunk is a culmination of countless hours of research and development. Here are just a few resources that have informed the Trunk methodology.
Scrum is defined completely in the Scrum Guide by Ken Schwaber and Jeff Sutherland, the originators of Scrum. The Scrum Guide is maintained independently of any company or vendor and therefore lives on a brand neutral site.
Atlassian's no-nonsense guide to agile development.
What is Agile?
Agile is an iterative approach to project management and software development that helps teams deliver value to their customers faster and with fewer headaches. Instead of betting everything on a "big bang" launch, an agile team delivers work in small, but consumable, increments. Requirements, plans, and results are evaluated continuously so teams have a natural mechanism for responding to change quickly.
Straight from the programming trenches, The Pragmatic Programmer: From Journeyman to Master cuts through the increasing specialization and technicalities of modern software development to examine the core process—what do you do, as an individual and as a team, if you want to create software that’s easy to work with and good for your users.
This classic title is regularly featured on software development “Top Ten” lists, and is issued by many corporations to new hires.