No theme, except for the place I bought them and picking them up really cheap:
Koontz, Dean R. (as K. W. Dwyer). Dragonfly. Random House, 1975. First edition hardback (“First Edition” and numberline starting with “2”, as per Random house practice), an Ex-Library copy with most of the usual flaws, including stamps at head and page block side, tape ghosts inside covers, spine lean, ink writing and some edge-staining on FFE; call it a Very Good- Ex-Lib copy, in a Fine- dust jacket with a bit of wrinkling at head and heel. Kotker, Dean R. Koontz: A Critical Companion, page 175. Bought at Half Price Books for $2.
MacAvoy, R. A. Trio for Lute. Nelson Doubleday (SFBC), 1984. First hardback and first omnibus edition thus (with code P08 on page 631, as per ISFDB), a Very Good copy with some dampistaining transfer to blind side of dust jacket, in a Very Good- dust jacket with same, as well as multiple small tears at head, slight wear at head and heel, and abrasions along rear flap fold. Signed by MacAvoy: “For Fred/Bertie/MacAvoy.” Almost certainly another book from Fred Duarte’s library. Omnibus edition of Damiano, Damiano’s Lute and Raphael. Bought for $2.
Morrow, James. The Madonna and the Starship. Tachyon, 2014. First edition trade paperback original, a Fine copy, signed by Morrow. Bought for $4.99.
(Pournelle, Jerry) Acres, Mark. Combat Command in the World of Jerry E. Pournelle’s Janissaries: Lord of Lances. Ace, 1988. First edition paperback original, a Fine- copy with some edgewear. These Combat Command novels were strategic “pick your own path” adventures. Sort of an oddball concept. I also have the one done for Zelazny’s Amber. Bought for $1.