It's never dull when we dive into BookFinder.com's dusty archives of digital data to compile a list of the most searched for out-of-print books from the previous year. Sex, religion, quilting, gardening, swimming, pike fishing, cooking and UFOs, you can find all the important aspects of life in this selection of literature.

Big names abound. Musicians Johnny Cash and Madonna are joined by actor Robert Redford. Writers like Stephen King, Patricia Cornwell, Pearl S. Buck, James Herbert, Isaac Asimov and Ray Bradbury are there too.

Once again Madonna is back on top where the Material Girl always loves to be. After tumbling to No. 3 in 2014, Sex by Madonna has reclaimed the top spot in the BookFinder.com list for searches conducted in 2015. We do have a copy of Sex in the marketing department at AbeBooks and it's pretty rude - we don't let the interns near it and the HR department doesn't know about it at all. I'm not sure what else we can say about this famous book where Madonna flaunts herself across a multitude of sexual preferences and lusty scenarios. I suppose we could add that the book does have sturdy aluminum covers which makes it rather durable and aluminum doesn't rust so that's another plus.

Putting Madonna and her antics to one side for another year, the BookFinder.com list continues to be a microcosm of modern society. It's a shame that so many of these books have slipped through the cracks and gone out-of-print. But there is always hope. A Treasury of Great Recipes by Vincent and Mary Price is missing after finally being reprinted in 2015 - 50 years after it was first published.

There are art books galore including instructional, educational and appreciations of the form. Sport - football, motor racing and open-water swimming - can be found alongside religion (Mormons, Muslims and Christianity), gunsmithing, and crafting.

With transgenderism discussed so much in 2015, it was interesting to see A Life Worth Living by Lady Colin Campbell make an appearance. The victim of a rare cosmetic disorder, she was wrongly registered and brought up as a boy in Jamaica. She did not receive medical treatment until she was 21 but went on to become a model.

Hagarism: The Making of the Islamic World by Patricia Crone and Michael Cook, originally published in 1977, is one of the many topical books on the list. Bandit Country by English journalist Toby Harnden offers a deep perspective on Northern Ireland's Troubles during the height of the conflict. The Evil of the Daleks by John Peel is a novelization of one of the BBC's 'lost' Doctor Who episodes from 1967.

R.H. Blyth - a long forgotten English author - has two books on the list. One about haikus and the other about Zen in literature. Blyth (1898-1964) was an expert in Japanese culture and even tutored the Japanese Crown Prince while working as a Professor of English in Japan.

Perhaps the most fascinating book on the list is The Sound of Music and Plants by Dorothy L. Retallack where the author measures the effect of music on plants. Apparently, plants enjoy, and will grow toward, middle-of-the-road music, but they die and shrivel up when exposed to rock and roll. Titles like this one prove that there is a book covering every subject you can imagine.