Not books, but some inspiring resources. FModel [0] is a set of patterns for functional reactive DDD on the basis of event sourcing. In particular the Decider pattern is a great way to model aggregates, and test them using Scenario's that read like Gherkin in code (given.. when.. then). Combines well with actors to represent aggregates.

On the BEAM used by Erlang, Elixir, and Gleam actors are called processes, and this guide [1] delves into domain modeling with them.

[0] https://fraktalio.com/fmodel/

[1] https://happihacking.com/blog/posts/2025/the-gnome-village/

Applied Akka Patterns by Michael Nash, Wade Waldron (Oreilly) was very digestible and relevant at the time, might be dated by now. Just read the intro to get the vibe.

These days I would recommend picking a framework and then ask claude & friends to do a deep dive with you and build an example project out. Ask it to explain concepts, architecture, trade-offs, scalability considerations, hosting considerations, compare it with other frameworks, hook it up to storage systems (sqlite, postgresql, blob storage) and so on. Try running them within a wireguard network and so on. Very interesting learning to be found.

You can always join the Orleans Discord