We published the hardcover version at LuLu.com: https://www.lulu.com/en/gb/shop/jacqueline-brassey/advancing-authentic-confidence_hardcover/hardcover/product-1kkvp9y2.html
And the softcover version can be bought here: https://www.lulu.com/en/gb/shop/jacqueline-brassey/advancing-authentic-confidence/paperback/product-1pg6ze6z.html
Since July 2020 also available via Amazon.com (paperback): https://www.amazon.com/Advancing-Authentic-Confidence-Jacqueline-Brassey/dp/0244192707/ref=sr_1_1?dchild=1&keywords=brassey+authentic+confidence&qid=1595748894&sr=8-1