Client-side Development and CMS. Some recent web development trends have CMS implications, most exemplified by the tagline of the New Dynamic (their capitalization), which promotes static site generation.
The Static Web: Static Site Generators and the Post-CMS paradigm.
By "The Post-CMS paradigm," it's clear they specifically mean the coupled CMS paradigm.
Workflow Theory. Beyond being a feature, workflow is a generalized theory. Workflow Patterns is a university partnership with the goal to "provide a conceptual basis for process technology." They have papers on topics like Workflow Control-Flow Patterns: A Revised View and they even have a book published now: Workflow Patterns: The Definitive Guide.
Book Recommendation. I've been reading Designing Connected Content by Carrie Hane and Mike Atherton. This book, and Content Everywhere by Sara Wachter-Boettcher (for which I wrote an amazing sidebar...) are a fantastic look at CMS from a content perspective. If you're in marketing or content strategy with limited experience in CMS implementations — or have such a client — these two books are a solid introduction.
CMS Expert Group. I've belonged to the J. Boye CMS Expert Group for a number of years now. It's a group of experienced CMS vendors, integrators, and users that meet four times a year to spend a full day discussing what we do. We have a guest speaker or two, and a couple members might give short presentations, but it always descends into in-depth discussion fairly quickly. Travel out of the Midwest is sometimes onerous, but I suffer through it because the group is that good and has been hugely influential in my professional development.
Content Managers Workshop Conference. My company, Blend Interactive, organized the Now What Conference for five years. For 2018, we're offering the Now What Workshops, which is four workshops over two days on content strategy and management(-ish) topics. This year we have four speakers coming in from all over the country. If you manage a website for a living, there's quite a bit here for you.
Two of the more CMS-ish workshops:
The First CMS? This question at Quora resulted in some interesting answers: When was the first web content management system (CMS) released? Various answers: FileNet (still around), Vignette (merged with OpenText) and RAINMAN from early AOL (proprietary/private, and likely long gone) are mentioned.