Arbain's collection of Imam Nawawi's hadiths are selected hadiths compiled by Imam Nawawi. Arba'in means forty but actually there are forty-two hadith contained in this book.
 
This book together is considered to be the work of Imam Nawawi who is very well known and accepted by Muslims throughout the world. In addition to the book Riyadhus Salihin, Imam Nawawi also authored this book; all of them became famous among students as memorization