Here is the full list of all 50 Black Book achievements.
Don't release the Mermaid
Acquire 100 sins
Guess all the Obderiha riddles with the first attempt
Succumb to Dark forces
Collect 4 copies of each card
Meet your beloved one
Complete Chapter 7
Unlock all the words
Unlock all the black words
Break all the seals
Complete Chapter 6
Retrieve the Book
Collect all the songs
Collect 70 encyclopedia entries
Complete Chapter 5
Complete Karnysh loyalty quest
Collect 50 bailichkas
Talk with 100 characters
Visit 333 locations
Complete Chapter 4
Find all the clues in Nemzya
Gather 66 herbs
Complete Chapter 3
Collect 30 bailichkas
Answer 40 Knowledge questions
Take seven demons to your service
Guess the road in the cursed forest
Read 77 entries in the Onomasticon
Complete Chapter 2
Release the Mermaid
Complete Proshka loyalty quest
Complete Old Egor loyalty quest
Cow level
Win 3 times in a card game while cheating
Gather 33 herbs
Release seven dead men
Complete White Head loyalty quest
Answer 25 Knowledge questions
Collect 30 encyclopedia entries
Compose a spell out of 13 words
Negotiate with Susedko on Zemskaia station
Complete Chapter 1
Complete Nikolay loyalty quest
Collect 10 bailichkas
Answer 10 Knowledge questions
Gather 13 herbs
Win 5 times in a card game
Collect 10 encyclopedia entries
Complete the Prologue
Become a mistress of Hell