The novel was first published in 1880 and has been in print ever since.

in 在这里表示"处于某种状态"。 print 作为名词时指"印刷品"或"出版物"的状态。 in print 是一个固定短语，表示"仍在印刷发行中"，指书籍等出版物持续有印本供应销售的状态。