Bihār al-Anwār is a comprehensive collection of traditions (ahadith).
Probably completed between 1106 AH (1694 AD) and 1110 AH (1698 AD), it is a compendium of ahadith (Hadith), historical subjects and commentaries on many Qur'anic verses.
Bihar al-Anwar has 110 volumes. Majlisi compiled it to gather all the ahadith he could access. His primary goal was to preserve the available knowledge for future generations. Majlisi has acknowledged this issue in the preface of Bihar al-Anwar, emphasizing that the traditions collected were not included without being subjected to scrutiny, a task in itself that was a major undertaking. Majlisi says, "Then I chose to examine the traditions of the infallible, righteous Imams, started exploring them and investigated them as was their right and I acquired its skill as was its due."
The collection is the most comprehensive (as a single collection) among all Islamic ahadith collections