Cliff Webb writes:
The Library has an unrivalled collection of parish magazines from all parts of England and Wales. As of today, well over 30,000 monthly magazines are either in the Library or awaiting transfer thereto.
There is a modern study of the parish magazine in the Library. ¹ I was pleased, however, recently to secure for it a much earlier item on a different aspect of the subject: The Parish Magazine by the Rev. J. M. Swift, M.A., vicar of Garston, Liverpool, A.R. Mowbray, London and Oxford, 1939.
John McIntosh Swift (1 Feb 1886-25 Apr 1949) came from a mining background (his father was a colliery secretary, who took the trouble to correct the baptism entry 18 years later from ‘labourer’. He secured entry to St John’s College, Cambridge, and became secretary of the Liverpool Diocesan Press and a canon of Liverpool Cathedral. He wrote several books on history as well as this one.

Swift’s short (48 page) book is designed to give guidance to editors. Much of it would be as applicable today as in 1939, but inevitably there is a lot of obsolete material.
His statistics are, however, of interest. In 1936, there were 11,085 parish magazines, with a combined circulation of 2,763,000. I wonder what the circulation figure would be today? One fears substantially less, though most parishes still manage a monthly magazine, even if in collaboration as a group.
[1] Subscribing to Faith? The Anglican Parish Magazine 1859-1929 (Histories of the Sacred and Secular, 1700-2000), Jane Platt, London, 2015.