S.M. Ulam, Problems in Modern Mathematics, John Wiley and Sons, 1959.
The Scottish Book, mathematics from the Scottish Cafe, ed by R.D. Mauldin, Birkhaüser, 1981.
Open Problems in Topology, ed by J. van Mill, G.M. Reed, North-Holland, 1990.
D.H. Fremlin, Problems to add to the gaiety of nations, fremdh@essex.ac.uk
M. Scheepers, The Boise problem book, marion@cantor.idbsu.edu
Victoria Delfino Problems, Cabal Seminar, Lecture notes in mathematics, 689, 839, 1019, 1333, Springer-Verlag.
Analytic Sets, ed by C.A.Roger, J.E.Jaynes, Academic Press, 1980.
B.Velickovic, Some problems in set theory, Jan 1995, boban@logique.jussieu.fr
H.Friedman, 102 problems in logic, Journal of Symbolic Logic, 40(1975), 113-129.