The essays were highly influential, and contributed to Knight's stature as the foremost critic of science fiction of his generation.

In the opening chapter, Knight states his "credos", two of which are: That science fiction is a field of literature worth taking seriously, and that ordinary critical standards can be meaningfully applied to it: e.g., originality, sincerity, style, construction, logic, coherence, sanity, garden-variety grammar.

That a bad book hurts science fiction more than ten bad notices.One essay in the book is "Cosmic Jerrybuilder: A. E. van Vogt", a review of the 1945 magazine serialization of A. E. van Vogt's The World of Null-A, in which Knight "exposed the profound irrationality lying at the heart of much traditional science fiction".

The third edition, published 1996, interwove additional chapters, including personal reminiscences: Anthony Boucher described the original edition as "a comprehensive picture of the book publication of science fiction in the 1950s, valuable as a historical record, stimulating as a detailed analysis of faults and virtues, and delightful simply as good reading matter in its own right",[5] P. Schuyler Miller reviewed the book favorably, saying that Knight "applies his rules honestly and mercilessly", although he also noted that Knight's close focus on technical aspects of writing sometimes ignored an author's ability to "cast a spell .

[6] Reviewing the second edition, Algis Budrys declared that "Damon Knight sets an as yet unequalled standard" for sf criticism, and praised Knight both for "his exact appreciations of the well done" as well as "how influential [he] was when summing up the subtle but suddenly obvious flaws in work that had seemed pretty good".