In Purest Sorrow (Polish: W żalu najczystszym) is a hand-made volume of poetry by Krzysztof Kamil Baczyński from 1942.

[3] The volume was the poet's wedding gift to his wife, Barbara Baczyńska (née Drapczyńska).

[3] The manuscript consists of 20 thick, light brown leaves sewn together with cotton filament.

[3] Each of the 18 poems in the volume, written in Baczyński's own hand, opens with a large colourful initial.

[3] The manuscript was purchased by the National Library of Poland in 1963 from Baczyński's mother-in-law, Feliksa Drapczyńska.