This information memorandum of the Wisconsin Legislative Council describes two pieces of state legislation: 1987 Wisconsin Act 355, which revises the laws relating to child custody determinations in actions affecting the family, and 1987 Wisconsin Act 364, which clarifies and revises the initial applicability provisions in Act 355. Part I of the memorandum presents highlights of Act 355 as affected by Act 364. Part II gives a background report on major child custody issues, including discussions of the Legislative Council's Special Committee on Custody Arrangements, definition clarifications, child custody dispute resolution procedures, the joint custody award system, the standard for change in custody, removal of child's residence, and visitation rights of nonparents. Part III contains a description of 1987 Wisconsin Act 355, as affected by 1987 Wisconsin Act 364 and includes sections on: (1) definitions; (2) joint legal custody; (3) periods of physical placement and visitation rights of nonparents; (4) additional factors in custody determinations; (5) mediation of legal custody and physical placement disputes; (6) standards for modification of legal custody and physical placement orders; (7) change of residence of legal custodian and child; (8) guardian ad litem legal education requirements and other guardian ad litem provisions; (9) access to records; (10) family court commissioner's information services; and (11) initial applicability of the acts. Statutes applicable to rebuttable presumption in the new joint legal custody law are appended. (NB)