A poetry collection is often a compilation of several poems by one poet to be published in a single volume or chapbook. A collection can include any number of poems, ranging from a few (e.g. the four long poems in T. S. Eliot's Four Quartets) to several hundred poems (as is often seen in collections of haiku). Typically the poems included in single volume of poetry, or a cycle of poems, are linked by their style or thematic material. Most poets publish several volumes of poetry through the course their life while other poets publish one (e.g. Walt Whitman's lifelong expansion of Leaves of Grass).