W.M.R. was ??

W. M. R. is William Mason Roberts (1869-1933). For details of his biography see Noel's History, vol. 1, page 143-144. (I don't think that he had any relation to Theodore Roberts.) WMR's booklet is mentioned in Noel's History, vol. 2, p. 424 (footnote), though the title is given there as "Modern Attacks on our Lord Jesus Chrtist". But the Publisher is the same and the slight differences in the Title are probablya a mistake by N. L. Noel.

Thanks!
CBA lists an item with the longer title too, so I guess both were issued.