An early collection of Humument pages, garnered from the cutting room floor of A Humument and published as a precursor. In the Preface, Tom Phillips wrote:

Trailer was assembled in the evenings between February 1st and March 1st 1970. Some of the pages correspond closely to pages of A Humument itself (pp.2, 6, 18, 21, 26) although most of the work consists of variations of wording and drawing, and pieces that do not occur at all in the full version or even could not (by virtue of their already having been obliterated). 

Trailer has also given me a chance (for instance in p. 8, dedicated to Christian Wolff the composer, and referring to his piece `Stone’) to catch up on some lost opportunities in my initial working of the text. It has also enabled me to rescue from oblivion some other by-products of A Humument (notably pp.7 and 29 which together formed part of a cover, rejected by the London Magazine).

Although p.75 is manifestly the end, the book has no real sequence, only a preferred order mainly based on the visual elements. However, there is a mood pattern in addition to the visual structure and the book is meant to be considered as a self-contained work.