This act recognizes that it is in the Indian child's interest to encourage and protect their membership in tribe and connection to tribal community.
It creates an affirmative duty, in any case involving minors, to inquire whether the child in question is an Indian child.
Federal:
25 USC Sections 1901 et seq.
25 CFR Sections 23.1 et seq.
BIA Guidelines for State Courts ( Fed Reg 67584)
CA State:
Welfare & Institutions Code section 224
Probate Code section 1459 et seq.
California Rules of Court section 5.480-5.488.
Other useful links:
The ICWA establishes minimum procedural and substantive Federal standards that govern the removal of Indian children from their families and subsequent placement in foster or adoptive homes.
In 1978, acting in response to concerns about the high rate of Indian children being removed from their families or placed in non-Indian homes, Congress passed the Indian Child Welfare Act (ICWA) (25 USC 1901-1923). The overall goal is the stability and integrity of not only children, but tribes and culture. Basically, a child custody proceeding involving an Indian child is the same as any other, only under the ICWA not only are the child's interests considered, but the interests of the child's Indian tribe as well.
There are two main prongs to consider: (1.) whether the proceeding is one covered by the Act, and (2.) whether the child involved is an "Indian 
child" as defined by the Act.
There is an affirmative duty to inquire whether the subject child is an Indian child, as defined by the Act, and this duty extends not only to parties, but to counsel, agencies, and anyone connected with the action.
If both prongs are present, then the ICWA applies and all provisions must be followed.