All Richard Underwood authored books are now free, and the can all be downloaded from this website in pdf format or in epub and Mobi formats.
They have also been made available free of charge on all the major online booksellers including Amazon, Apple Books, Kobo, etc.
Once existing stocks have been sold you will no longer find them on bookshop bookshelves because new editions are no longer being printed. However, they should all still be available as free downloads from those same bookshop’s websites.
I’ve added the reasons for making all my books free to the FAQ page, available from the FAQ link at the top of the page.