Was very helpful to read other Goodreads comments after starting the book as I found it quite confusing. But really liked it once I got used to the deuces: two people Pym was writing to (Tom/Jack), the switching of persons telling the story (first person/third person), and the two time periods (past/present). Hated the ending but it made perfect sense. Also, as the book unfolded, Pym's profound decisions became clear too.
My question at the end was this: how did he become who he was? First thought was 50% innate character, 40% father and 10% Jack/Axel. Then I thought 25% Pym, 75% father and 25% Jack/Axel. The latter makes more sense.
Would highly recommend.