IBooks Author uses ibooks extension and ibook is usually a mistype. So it is likely you were looking for IBA to IBOOKS conversion. Anyway, only iBooks Author can perform this conversion, no 3rd party software supports this conversion.
Convert iBooks Author e-book to iBooks e-book file.
We found one software available in the database for this conversion.
Apple macOS / Mac OS X software - convert iba to ibook on OS X
Apple's free authoring tool for making great looking e-books for iPads
Convert from iba file format
|Yes, iBooks Author supports iba file conversion as a source file type.||Yes||Yes||iba editor||No||No||No||No|
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.