I just finished Unlucky Charms and am currently part-way through reading all four of these books. I’ve read The Hobbit and The Barsoom Project before (the latter because I read it a long time ago; and now that I’ve found a fourth book in the series, I’m re-reading the first three before getting to the new one). The other two are new to me, although I’ve read other things by both authors before. (Rob Grant was also one of the co-creators of Red Dwarf.)
Click on the picture for a close-up of that sticker on the cover of Incompetnḙce. I found it amusing.