After the Qur'an, the prophetic traditions (ahadith) are the most recognised source of wisdom in Islam. Amongst the collected Hadith, Sahih Muslim is second only to the collection of Imam Bukhari (his magnum opus: Sahih Bukhari).
Hadith(plural: Ahadith): literally means a saying or a statement. It refers to statements (or narrations) that are attributed to Prophet Muhammad (ﷺ/peace be upon him).
The ahadith have been narrated by the Prophet's ﷺ companions, and have reached us through individual, reliable narrator(s) in every generation. The authenticity of a hadith is derived from the narrators (whether they were trustworthy, honest, had good memory etc). Sahih in Arabic is a term used to describe authenticity.
In this series of Sahih Muslim there is an extensive commentary by Imam Nawawi, whose other works are amongst the most widely-read books on Islam and translated by Adil Salahi, a modern scholar of great acclaim. This immense work is finally available to English readers. It is an essential addition to every Muslim library as well as for anybody with an interest in Islamic thought.