It is . . . . . . . . interesting book. It gives . . . . . . . . wonderful picture of what . . . . . . . . life was like in . . . . . . . . Victorian times.

The first and second blank shall take the indefinite articles 'an' and 'a' respectively because the first blank is followed by a word starting with the vowel 'i' and 'interesting book' represents a singular countable noun and the second blank is followed by 'wonderful picture' which represents a singular countable noun and is followed by a word starting with the consonant 'w'.
The third blank shall take 'the' as the sentence talks about Victorian people which shows particularity. The fourth blank won't take any article as 'Victorian times' is uncountable and represents no specific time.