In which books we can find representations or character tables, Sylow 2-subgroups and conjugacy classes for finite simple groups and their Schur covering groups and properties for Schur multiplier of finite simple groups?
The following websites may be useful to my questions:
Beyl-Tappe [4] say on p. 119:
5.9 REMARK. The Schur multiplicators of all finite simple groups have been found, often by exhibiting a universal perfect cover (representation group). For the results see the summary by GRIESS [2] and follow the references given there.
[1] Griess, Robert L. jun., Schur multipliers of the known finite simple groups, Bull. Am. Math. Soc. 78, 68-71 (1972). ZBL0263.20008.
[2] Griess, Robert L. jun., Schur multipliers of the known finite simple groups. II, Finite groups, Santa Cruz Conf. 1979, Proc. Symp. Pure Math. 37, 279-282 (1980). ZBL0448.20014.
[3] Griess, Robert L. jun., Schur multipliers of the known finite simple groups. III, Proc. Rutgers group theory year, 1983/84, 69-80 (1984). ZBL0648.20017.
[4] Beyl, F. Rudolf; Tappe, Jürgen, Group extensions, representations, and the Schur multiplicator, Lecture Notes in Mathematics. 958. Berlin-Heidelberg-New York: Springer-Verlag. IV, 278 p. DM 33.50 {$} 13.50 (1982). ZBL0544.20001.
If you really search for a book on most of those topics (at least character tables and conjugacy classes) for simple groups with some proofs, the best (and most compact) ones might be those of Gerhard Michler : Theory of Finite Simple Groups Part I and II.
