Transcribed by hand by John Septimus Roe, they are the source of best provenance for the majority of the journals' contents, the originals of which have been lost in most cases.
As a result of his efforts, Western Australia has an exceptionally good record of its early explorations, nearly every significant journal being extant from 1827 until Roe's retirement in 1870.
The Survey Office retained Roe's Letterbook, and continued to hold journals and reports, but no attempt was made to collate or archive these in a sensible manner.
However, they are not entirely reliable: many words, including some names of places and people, were transcribed incorrectly in the making of the 1920s transcript.
It is now lodged with the State Records Office of Western Australia, where it is given item number 328 of Series 2117.