Some Muslims who are either ignorant or of weak faith still commit many acts which Allah never allowed. Ignorance is not an excuse for doing Muharramat, hence is the importance of such books which deal in detail with many Muharramat that should be consciously learnt and consequently never committed.
The author. Sheikh al-Munajjid. has dealt with matters such as calling for help from sheikhs, saints and things other than Allah; worshipping the dead and circumambulating their graves; invoking prophets, using magic and fortune-telling and believing in astrologists and planets, etc.
As such, this book of prohibitions in beliefs and worship acts is a must to almost every Muslim, if he/she is really practicing Islam and wants to be safe and free of great sins.