Create subfolders, move files
I would use the shell in such a case.
Open Terminal and enter cd path/to/Audiobooks/Books, then run
find . -type f -name '* - *' -maxdepth 1 \
    -exec bash -c 'mkdir -p &quot;${1%% - *}&quot;; mv &quot;$1&quot; &quot;${1%% - *}/${1#* - }&quot;' _ {} \;

PS: This assumes that you want to move all files in that folder and that Author and Title are always separated by - .

This uses find to find all matching (-name '* - *') files (-type f) in the current directory (-maxdepth 1) and then executes the bash ... \; part on each of them. The executed part is basically a bash script which gets the filename in $1 and then uses text substitution to extract author and title (${1%% - *} cuts off the part starting with -, ${1#* - } cuts of the part ending with it).