The Epistle to the Hebrews (abbr. Heb for citations) is one of the books in the New Testament. Though traditionally credited to the Apostle Paul, the letter is anonymous and most modern scholars, both conservative and critical, believe its author was not Paul himself but some other member of his Pauline community.
The letter has carried its traditional title since Tertullian described it as Barnabae titulus ad Hebraeos in De Pudicitia chapter 20 ("Barnabas's Letter to the Hebrews".)
(Summary from Wikipedia)