"Her studies had been unsystematic and without any real objective, at least until she wandered into the university bookshop on Miami and came out with 'Dimensions in Mathematics' by Dr L.C. Parnault (Harvard University Press, 1999)."
Salander, hooked on spherical astronomy, has this book as an almost constant companion for the rest of the book.
'Dimensions in Mathematics' turns out to be a fictional book of Larssons own creation. Follow this link to read what Harvard University Press have to say about it: