The true identity of "Martin" has long been speculated upon. Many have suggested John Penry, who was hanged in 1593, others Edward de Vere and Christopher Marlowe. As the tracts had to be printed in secrecy, some sort of organisation was clearly involved to handle their production and distribution, and as their intent found widespread support among the Puritan element, some sort of communal authorship is likely.
Penry was definitely involved in the printing, and his press was frequently relocated to different parts of the country in order to avoid the authorities. He himself denied any involvement in the actual authorship.
The government was concerned enough at the virulence of the attacks on the ecclesiastical hierarchy to respond in kind, hiring professional writers such as Thomas Nashe, Robert Greene and John Lyly to write counter-tracts. Like most polemics, the tracts are full of hatred of their opponents, describing the bishops as representing the Antichrist, and equally convinced of the righteousness of their own cause.