The Rosicrucian manifestos are a collection of several long-form interconnected allegorical essays and stories, suggesting in brief the existence of an esoteric reformation fraternity of sorts. They are interesting for their historical significance, and as a sort of prefiguration of the more familiar secret societies that came later.
In form, these writings recall other intensely allegorical / spiritual-symbolic works. I am reminded of Jodorowsky's The Holy Mountain, or Daumal's Mount Analogue. Themes of personal purity, hardship and danger, revelation, visions, etc.
In content, I can only really compare this to the much later Western esoteric currents that emerged in the spiritualist tradition in the late 19th / early 20th century. The revelation of secret traditions brought back from the crucible of the mysterious East is not only the exact formula used here, but also by the much later Blavatsky, Gurdjieff, etc. In contrast to those authors, the Rosicrucians here framed their secret knowledge as firmly Christian in essence, although still marking a return to a more pure, preserved current.
The probable role of these manifestos in instigating or announcing the social / epistemological upheavals of the enlightenment, renaissance, reformation, etc. is intriguing but I am not at all an expert on the subject.
The essays that precede the text in this edition are very helpful and to me, more interesting than the manifestos themselves for their helpful historical context.
Kind of a fun thing to read as an original source text for much Dan-Brown-style historical speculation, with lots of mystery, hidden secrets, and symbols to decode.