In [Figure 43], “ISGAY” was corrected to “ISGAU” to match previous figures and to correct spelling in the plaintext.
In [Chapter VII], “those who like method” was corrected to “those who like this method”.
In [Chapter XVIII], “misuse of the Type II slide” was corrected to “misuse of the Type I slide”.
In [Figure 139], “IQCIO” is corrected to “IQVIO”.
In the [Appendix], in the list of English trigrams, “WHI 51” was corrected to “WHI 71”.
Some corrections were made to the exercises in order to rectify the spelling in their plaintexts or (in one case) to resolve an inconsistency in its key.
In [exercise 33], seven letters were missing. The uncorrected cryptogram is VINSC FEAEO OHSEF HLEHU NSTNC LTSLC IAESH RHSIR ERMTS ETEPD TOINM RTTHT TLRUB E.
[Exercise 110]: “LRSFQ” corrected to “IRSFQ”.
[Exercise 115]: “FBEHZHWU” corrected to “FBEHZHWG”.
[Exercise 116]: “HVIYF” corrected to “HVXYF”.