Hasta luego

 I sure hope you like it guys like the book.

fabrizio says

en este caso "tratar" no significa "to try". "Tratarse de algo" significa "to be about something".

- De que se trata? (What's it about?)

- Se trata de algo importante. (It's about something important.)

Ok, I am trying to get my head wrapped around that idea.

I went off looking for other examples, and came up with a few and in many cases "about" does seem a good translation.

se trata / tratarse ties to a noun or pronoun and sets up a relationship.  About is about a testing of qualities. It is a comparative test that selects qualities near the associated nomnitve. I think we are still on the try, test, playing field.

JP seems to have translated it as "happens" which lead me to think that a more literal version of attempt, try to fit, compare --- as action might fit.

FWIW here are the examples I dug up.

Cuando se trata de algo más que un estado de ánimo

Sentirse irritable o con temperamento fácil de exaltar pueden ser signos de depresión.

When It's More Than Just a Mood

Feeling irritable or short-tempered can be signs of depression.

........
Entonces, cuando se trata de algo que caracteriza a un sujeto que ni es persona, ni animal, sino que es algo abstracto o un objeto...

.........
Usamos "do" cuando se trata de algo que se considera trabajo:
To do work/homework
To do the shopping
To do the cooking

Usamos "make" que se trata de algo creativo:
To make a cake
To make a sweater (hacer un suéter)
To make a film

........
Cuando se trata de algo personal, el deporte es portada.

aquí hay unos ejemplos de los usos de "tratar" que me guardé de otra discusión aquí en Spanishpod:

- tratar algo o alguien= to look after, to take care of.

Trata mal a su perro. He looks after his dog badly.

Trátalo bien. Take care of it.

- tratar + de/sobre = to be about.

Trata de una chica que... It´s about a girls that...

La peli trata sobre una historia de amor. The movie is about a love history.

- tratarse + de = to be

Se trata de una chica muy problemática. She is a very problematic girl.

Se trata de una novela muy interesante.it is a very interesting book.

- tratar + de + infinitive verb = to try to

Trato de hacerlo bien. I'm trying to do it properly.

Está tratando de pintar. He is trying to paint.

Sorry to have led you astray, mgirll.

Estoy tratando de pintar ahora :)

I am trying to paint now :)