.ark files are proprietary files to the Open Book program. .kes files are proprietary to the K1000 program. Hence, they are only openable by their respective programs and, unless someone were familiar with these programs, the extensions might seem a bit strange. There are certain advantages to uploading in these proprietary formats as it forces validations by these programs and formatting, pagination, et al won't be accidentally undone by another word processor. The big disadvantages are that the files are larger and that the field of potential validators for these books are less. To unsubscribe from this list send a blank Email to bksvol-discuss-request@xxxxxxxxxxxxx put the word 'unsubscribe' by itself in the subject line. To get a list of available commands, put the word 'help' by itself in the subject line.