La postfazione riguarda l'ambientazione.

La is the singular feminine definite article, meaning the.

It is used because postfazione is a feminine singular noun:

• la postfazione = the afterword

In Italian, articles must agree with the noun in gender and number.

Postfazione means afterword: a section at the end of a book, usually added by the author or another writer.

It is a real and standard Italian word, though it is more literary or book-related than everyday vocabulary. It is the opposite of prefazione (preface).

• prefazione = preface
• postfazione = afterword

Riguarda here means concerns, is about, or deals with.

It comes from the infinitive riguardare.

So:

• riguardare = to concern / to be about
• riguarda = it concerns / concerns

In this sentence, the subject is la postfazione, so riguarda is in the third person singular.

Because the subject is singular:

• La postfazione = singular

So the verb must also be singular:

• La postfazione riguarda... = The afterword concerns...

If the subject were plural, you would use riguardano:

• Le postfazioni riguardano... = The afterwords concern...

The apostrophe appears because la becomes l' before a feminine singular noun beginning with a vowel.

So:

• la ambientazione ❌
• l'ambientazione ✅

This is called elision.

Other examples:

• l'amica = the (female) friend
• l'isola = the island
• l'idea = the idea

Ambientazione usually means setting, especially in literature, film, or storytelling.

It refers to the world or context in which a story takes place, such as:

• the place
• the time period
• the atmosphere or background

So it is often broader than just location.

For example:

• l'ambientazione medievale = the medieval setting
• l'ambientazione del romanzo = the setting of the novel

Because riguardare is normally a direct transitive verb in Italian. That means it takes a direct object without a preposition.

So Italian says:

• riguarda l'ambientazione

not:

• riguarda di/per/su l'ambientazione ❌

This is different from English, where we often say is about.

Compare:

• Il libro riguarda la guerra. = The book concerns war.
• La discussione riguarda il finale. = The discussion is about the ending.

Yes, that can work in some contexts, but it is not exactly the same.

• La postfazione riguarda l'ambientazione sounds more neutral, precise, and slightly more formal.
• La postfazione è sull'ambientazione is closer to The afterword is about the setting and sounds a bit more conversational.

So both may be understandable, but riguarda is a very natural and elegant choice here.

The standard order is:

• La postfazione riguarda l'ambientazione.

Italian word order is often flexible, but this version is the most neutral and natural.

You could change it for emphasis, for example:

• L'ambientazione la riguarda la postfazione ❌ awkward/unusual
• Riguarda l'ambientazione, la postfazione ❌ not natural in normal usage

So for a learner, the best choice is to keep the basic order:

subject + verb + object

A helpful approximate pronunciation is:

la post-fa-TSYO-ne ri-GWAR-da lam-byen-ta-TSYO-ne

A few notes:

• zione is usually pronounced like tsyoh-neh
• giu/guar in riguarda has a hard g sound
• l'ambientazione flows together smoothly because of the elision

If you want to pronounce it more carefully by syllables:

• La po-stfa-zió-ne ri-guàr-da l'am-bien-ta-zió-ne

It is neutral to slightly formal.

The vocabulary makes it sound like something you might read in:

• a book review
• literary commentary
• an academic discussion
• publishing-related writing

The verb riguardare is very common and perfectly normal, but together with words like postfazione and ambientazione, the sentence has a fairly literary feel.