here is my way.. (not working on all ebooks..)

dump EXE in unpacked form..

use mlti-ripper to extract images..

use editor to locate the HTML files.. (this one is time consuming..)

in end.. each type of EXE-ebook needs different approach..

but i think there is a better way .. as all EXE-ebooks are using the windows builtin-HTML engine used in IE .. to it must dump the content a place..
memory .. is rather empty .. (this is from the EXE features..)

still this field needs to be explored..