Explanation

• The Hadith book in which all the Hadith reported by a particular companion are compiled is called Mustadrak
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• Al-Mustadrak 'ala al-Sahihayn كم) is a five-volume hadith collection written by Hakim al-Nishapuri (Nishapur is located in Iran).
• He wrote it in the year AH 393 (1002–1003 CE), when he was 72 years old. 
• Mustadraks have been authored for various subjects such as Jurisprudence, Rijal, Hadith etc