Six short lines, three couplets, and one word doing nearly all the work. "Read" opens each of the first three lines and returns at the very end, and the poem is the journey between those appearances: from someone who does something to someone to whom something is done.
The situation is simple. A person reads alone and keeps going, "till I am cross- / grained," until the solitude begins to wear on them. But the second half of the poem undercuts the word "alone." The speaker turns out to be "full of strangers," presumably the writers, narrators and characters who have crowded in during all those hours. The loneliness of the first couplet is a very populated loneliness. The central idea is that reading is a solitary act that makes you less singular: you sit by yourself and end up a host, and finally a text, "I am read."
That last line is the most interesting in the poem because "read" can be heard two ways. On the page, it looks identical to the verb that opened the poem. In the ear, it can be the past participle, pronounced "red." So "I am read" might mean "I am being read" by those strangers, or it might mean "I am well read," made of what I've taken in. The poem doesn't choose. One might even catch a faint pun in "cross" and "red," the colour of a bad temper, though that is an inference rather than anything the poem insists on.
"Cross-grained" is the poem's one piece of vivid imagery, and it is a sharp one. It is a woodworker's word for timber whose grain runs against the straight, which makes it awkward to cut or plane, and it is also a word for a contrary, irritable person. Since paper is made from wood, it is hard not to think of the book itself in the background, so the reader is roughened by the very material they are absorbing. The line break also splits the word in two, with the hyphen dangling at the end of "cross-." The word is interrupted, just as the speaker's mood has been.
The syntax holds a quiet trick. "Grained I am" is inverted, and it ends on "I am," which the next couplet can finish: "I am / full of strangers." The phrase serves two sentences at once, caught in the gap between the stanzas. Reading aloud, you can't quite say where one statement ends and the next begins, which is fitting for a poem about a self that has lost its clean edges.
The poem has no end rhyme, but it has other kinds of music. The repeated "read" acts like an identical rhyme, a stutter that mimics the compulsion of turning pages. "Grained" and "strangers" share the same long vowel and nearly the same sound pattern (gr-ain-d, str-ain-gers), so the irritable surface and the crowd beneath it are linked by sound. The syllable count swells and shrinks: two, four, five, three, four, three. The longest line is "read till I am cross-", the point of greatest strain, after which the lines tighten again. Almost every word is a single syllable, with only "alone" and "strangers" longer. Those two words, the poem's central opposition, stand out for that reason.
What makes the poem significant is how closely it enacts what it describes. It is titled "Reader," and as we read its repeated verb we take on the role of the "I" ourselves. By the last line, "I am read" lands on us as well: for a moment we are full of this speaker's voice, one more stranger inside someone else. The poem is also not simply cosy about the idea that books are company. "Full of strangers" carries some unease, as if being inhabited has a cost, and "cross-grained" suggests the cost is paid in temper. In so few words, it manages to hold both the comfort and the strain of a long evening alone with a book.