Self publishing
The market for self-published books is booming. Of the fifty top-selling Amazon eBooks as of February 22, 2022 at 9:00pm (and yes, the list is updated hourly,) 19 are self-published. Another 11 are published by Amazon in-house imprints Montlake, Lake Union, and Thomas & Mercer. Just 20 are from traditional publishers like Penguin or Harper Collins. KDPRocket reports that the best-selling of the indie books (The Rake, by L.J. Shen) has $418,471 in monthly ebook sales, and the last of the indie books (The Plains of Laramie by C.J. Petit) has $42,093 in monthly ebook sales. Each book is also available in softcover formats, as well, so the total is actually higher.