Who is Joaquin from Pablo Neruda: Selected Poems and what is their importance?

Neruda wrote a poem entitled "The Absence of Joaquin," referring to Joaquin Sepulveda, who died in 1929 at the age of 29. He was a friend of Neruda's, and a fellow Chilean poet. In the poem that he wrote for Sepulveda, Neruda is memorializing him so that he can continue to exist. Neruda is pondering the idea of non-existence, and is toying with ideas of defying such status. He is doing his young, dead friend a favor by writing about him; he is immortalizing him. This is partially what Neruda strove to do for himself as well in his writing. He is trying to leave his stamp on the chaos of time and history.