This is the 3145th most frequent Turkish word.
dizinin
"Of the series" or "of the sequence."
Here, 'dizinin' is used in a possessive form coming from 'dizi' (series), indicating possession of 'son bölümünü' (last episode).
Dizinin son bölümünü çok beğendim.
I really liked the last episode of the series.
In this sentence, 'dizinin' again shows possession, referring to the series ('dizi') whose continuation is the book mentioned.
Kitap dizinin devamı olarak yayımlandı.
The book was published as a continuation of the series.
Here, 'dizinin' pertains to 'dizi' (sequence or arrangement), related to contextually where the movement is placed.