Just want to point out that Records are still part of the standard library, and can be important for integrating with Erlang code using records which you need to work with. Even though they are avoided in Elixir, because structs are better in every way, they are still alive and well in Erlang.
Some of the elixir bits are now out of date. (eg. it still has a section on Records)
But it touched on a lot of OTP topics that were missing from other places.
(this was before Benjamin Tan's book was finished)
At the time I remember Elixir in Action really made me finally understand the OTP concepts.