Resources on how to build custom WordPress Themes for beginners

Foundational Articles

• WP Codex Article on Theme Development

Books

• Theme Handbook

Written Tutorials

• Tutorial from Theme Shaper

Videos

• WordCamp Chicago 2014 - Heather Acton: Introduction to Custom Theming
• WordCamp Nashville 2013 - Steve Wilkison: An Introduction To Creating Custom WordPress Themes
• WordCamp London 2015 - Samantha Miller: The Basics of Unique Theme Development
• WordCamp Montréal 2013 - Kirk Wight: Fundamentals Of Theme Development
• And a lot of additional videos around theme development on wordpress.tv

Podcasts

I've not found a lot of developer-centric workpress podcasts that would allow me to learn about WordPress via audio. However, here are podcasts that seem to touch developer topics at least:

• apply_filters
• kitchensinkWP
• WordPress Breakdown

Theme Development Frameworks

Yeah, there exist theme development frameworks as well. See the list.

• Genisis Framework

Community

Places where WordPress developers hang out.

• ThemeShaper Blog, home of the Automattic theme devision
• StackExchange WordPress Q&A Site
  • Frequent questions on tag 'theme-development'

Other Resource Collections

• 35+ Resources to Become a Kick Ass WordPress Developer
• 11 Online Places To Learn WordPress Inside And Out (Paid And Free Options)
• The Best WordPress Podcasts (Ultimate List)