Rev. C. S. Harrison published several editions of his peony manual, but the names are inconsistent. The first book was published in 1903 or 1904... Harrison didn't copyright this first edition, because wanted it to be shared and quoted from to evangelicize his love of the peony. The first book says "A Manual on the propagation and cultivation of the Paeony" on the cover, but the title page says "C. S. Richardson's Paeony Manual", and the succeeding pages are all headed 'C. S. Richardson's Paeony Manual".

Subsequent editions drop the 'a' from the spelling of the plant's name, in favor of 'peony'.

The second edition is copyrighted, but continues the tradition of having differing titles on the cover and title pages. The cover has "A Manual on the propagation and cultivation of the Peony", but on the title page, "A Peony Manual: Giving up-to-date information regarding these Beautiful Flowers". The page headers again are titled "C.S. Harrison's Peony Manual".

There was a 3rd edition (from 1914?) called "A manual giving complete directions for the propagation and cultivation of the Peony", with all page headers as "Peony Manual".

The 4th edition (c. 1917?) has the same name on the title page as the 3rd, with a preface called "Reasons for issuing the Fouth Edition of The Peony Manual". Again, the page headers are titled "Peony Manual".

It seems likely that Harrison always called his book 'a peony manual' or 'the peony manual', regardless of what the publishers put on the covers or title pages.

My source for the bibliographic info is the HathiTrust Digital Library.