My book on Leśniewski, Leśniewski's Systems of Logic and Foundations of Mathematics, is coming out soon (it's already available on Springer's website). It is not my PhD dissertation. I wrote the whole book pretty much anew and only part of the material overlaps with my dissertation. And even the stuff that I already included in my dissertation is different: I re-worked the material to make it more accessible and slightly less boring (probably failing at least at the latter task). HT to Severi Hamari, who co-authored one of the chapters.