"Leans" is the condition experienced by a jet pilot as he leaves the Earth's gravity. The book brings together four chapter-books and the remaining poetry that completes the poet's twenty-three-year project Gravity as a consequence of shape started in 1982. The earlier two volumes were Gravity and Entanglement, published in 2004 and 2005. The work includes brief and clear descriptions of scientific vocabulary along with poetry that demonstrates enjambment and transformations of poetry derived from collage practice or a practice that uses more than occasion to inform the work all at once in the same place. The poetry continues and extends the poet's concern for how we know anything and what vocabulary humans use to describe it. The texts therefore draw on unusual as well as straightforward words to achieve a rich range from blend to disruption. This encourages the reader's confidence but also provides many instances of surprise.