Den där boken ska vara bättre än filmen, men författaren ska ha ändrat slutet nyligen.

Den där boken means that book.

Swedish often uses a double definiteness pattern with demonstratives like den här and den där:

• den där boken = that book
• den här filmen = this film

You get:

• den/det/de
  • demonstrative/adjective + noun in its indefinite form

So even though boken by itself means the book, after den där you use boken? Actually yes, in this fixed pattern it stays boken in common teaching descriptions because the noun appears with its definite ending in many cases of demonstrative use. Learners often best remember the whole phrase as:

• den där boken
• det där huset
• de där böckerna

In everyday Swedish, den där often points something out specifically, a bit like that ... there in English.

They depend on the gender of the noun.

• den där is used with common gender nouns
• det där is used with neuter nouns

Examples:

• den där boken = that book
  (bok is common gender)
• det där huset = that house
  (hus is neuter)

So in your sentence, bok is a den-word, which is why it is den där boken.

Yes, ska often means will / shall / is going to, but here it has a different use.

In this sentence, ska expresses something like:

• is said to
• is supposed to
• apparently

So:

• boken ska vara bättre än filmen
  = the book is said to be better than the film
• författaren ska ha ändrat slutet
  = the author is said to have changed the ending

This is a very common Swedish pattern when talking about information that the speaker has heard, but is not personally confirming as fact.

The difference is certainty and source of information.

• Den där boken är bättre än filmen
  = The speaker states it as a fact or personal opinion: That book is better than the film.

• Den där boken ska vara bättre än filmen
  = The speaker reports what people say or what they have heard: That book is supposed to be / said to be better than the film.

So ska vara makes the statement less direct and more second-hand.

Because ska ha + past participle is another reporting structure.

• har ändrat = has changed
• ska ha ändrat = is said to have changed / supposedly has changed

So:

• författaren har ändrat slutet nyligen
  = the author has changed the ending recently
• författaren ska ha ändrat slutet nyligen
  = the author is said to have changed the ending recently

This structure is very useful in Swedish for rumors, reports, and unconfirmed information.

This is the perfect infinitive after ska.

The structure is:

• ska ha ändrat

Breaking it down:

• ska = is said to / supposedly
• ha = infinitive of have
• ändrat = past participle of ändra (changed)

It works like English:

• is said to have changed

Compare:

• ska vara = is said to be
• ska ha ändrat = is said to have changed

So ha ändrat shows that the changing happened before now.

Because the sentence means the ending, not just ending in a general sense.

• slut = end / ending
• slutet = the end / the ending

Here, it refers to the ending of the book, so Swedish uses the definite form:

• ändrat slutet = changed the ending

This is very natural in Swedish when talking about a specific ending already understood from context.

Because bättre is the comparative form of bra.

Just like in English:

• good → better
• bra → bättre

So:

• bra = good
• bättre = better

And än means than:

• bättre än filmen = better than the film

Using mer bra would sound unnatural in standard Swedish, just as more good sounds unnatural in English.

Än means than in comparisons.

Examples:

• större än = bigger than
• dyrare än = more expensive than
• bättre än = better than

So:

• boken ska vara bättre än filmen
  = the book is said to be better than the film

A common learner mistake is confusing än with att or som, but in comparisons with adjectives/adverbs, Swedish normally uses än.

Nyligen means recently, and placing time adverbs near the end of the clause is very common in Swedish.

So:

• författaren ska ha ändrat slutet nyligen

sounds natural and neutral.

You could sometimes move adverbs around for emphasis, but the final position is very common, especially in ordinary statements.

Learners should notice that Swedish word order is often flexible with adverbs, but not random. The default placement here is perfectly natural.

Because after a modal verb like ska, Swedish uses the infinitive of the next verb.

Patterns:

• ska vara = shall/will/is said to be
• ska ha ändrat = is said to have changed

This is similar to English:

• will be
• is said to have changed

So the modal/helper verb comes first, and the main verb follows in infinitive form:

• vara
• ha

Then, if needed, you add a participle:

• ändrat

Yes, in this sentence men works just like but.

It connects two contrasting ideas:

• Den där boken ska vara bättre än filmen
• men författaren ska ha ändrat slutet nyligen

So the sentence sets up one piece of information and then adds a contrasting or additional point.

Yes — very much so. That is one of the most important things to notice.

Both parts contain ska in a reporting sense:

• ska vara
• ska ha ändrat

That gives the whole sentence a tone of:

• reported information
• hearsay
• something the speaker has heard rather than personally verified

So a native English speaker might think of the tone as:

• Apparently that book is better than the film, but the author is said to have changed the ending recently.

That nuance is one of the key grammar points in the sentence.