Printed in a variety of typefaces, the poems in Edges overtly reference a number of important twentieth-century artists, including Kurt Schwitters, Paul Klee, and Constantine P. Cavafy.

The collection is divided into four parts: a group of love poems; an assembly of prose and poetry exploring Jungian and Freudian concepts, dedicated to Elizabeth Smither; the title work, which takes as its starting point a colorful, wooden necktie that artist Maurice de Vlaminck wore; and finally a section of poems and illustrations that playfully reimagine elocution exercises.

The Tram Conductor’s Blue Cap makes frequent allusions to Ancient Greece, with references to Asclepios, Plato and Troy, as well as poems titled "Translating Narcissus" and "Anecdotal Aesthetics in Athens."

"[10] Terry Locke, reviewing the collection for English in Aotearoa, described Harlow as "at the peak of his powers" and as someone who is "in the top echelon of New Zealand poets currently practicing their craft.

Previous to its publication, it received the 2015 Kathleen Grattan Award, which is biennially given to "an original book-length collection of poetry by a New Zealand or South Pacific permanent resident or citizen.

Fuelled by his musical background and his understanding that “Poetry is when words sing,”[13] the poems display lyric and rhythmic qualities characteristic of Harlow's previous work.

The book also draws upon Harlow’s background as a Jungian therapist, as many of the poems reflect the intangibility of their subject matter: existence, temporality, love, and mortality.

Responding to the collection, Emma Neale wrote that “Harlow’s poems are small detonations that release deeply complex stories of psychological separations and attractions, of memory and desire.”[14] Nothing for it but to Sing was generally well received.

And who’s going to complain about that?”[15] In her review for NZ Poetry Shelf, Paula Green wrote, “This shiny, ethereal collection, full of paradox and light, follows curved lines, follows song.

As New Zealand author Fiona Kidman has written, "Harlow is a distinguished and serious writer, dealing with big issues: life, death, sorrow, the inner consciousness, yet there is a bubble of gaiety, a vitality, never far from the surface".