Let's Talk About Sects, Baby
Jewish Denominations (and Non-Denominations), A 'Splainer

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Over the years, I've seen requests from y'all come in that boil down to the ask to better understand denominational theology, if I understand it correctly.
We'll get back to the Annotated Maimonides project, don't worry, but I've been incubating for a bit and thought it might be helpful to send it out of the nest at long last.
Because no, Reform Judaism is not Diet Orthodoxy; these movements, below– some of which are actual formal denominations, some of which are... not– have independent theologies and approaches to Jewish law, ways of thinking about and engaging with modernity, community, and/or other core issues that undergird them philosophically.
So I'm going to do a lil' explainer, the best that I can. (Invariably, someone will be upset. I'm sorry in advance.)
The first thing I want to say is that much of the crux of the matter, for our purposes today, will be about what is Torah– what happened in the Revelation at Sinai, from which flows who wrote the Torah, what is Jewish law, how much can we change Jewish law, what's our relationship to modernity, and all sorts of other things.
The second thing I'm going to say is that this is all the stuff on paper– there's so much more to say about what things look like in practice, what the tea is, all that. If you're interested in checking out a community, do that. Decide for yourself. I've given you some keywords– those things in a search engine, plus "Judaism" and your geographic area can probably get you some results. Noodle around, try things, etc.

Whether you're a Jew who wants to connect or reconnect, or a seeker investigating Judaism, this might be useful for you.
There are, of course, lots of other questions: What is God? How do we conceive of God? What happens when we pray? Etc. But those have a wide range of answers across traditional Judaism even before the denominations, so this really is the easiest place to plant our flag.