The CFR lists the rules currently in force (as of the date of the volume). These have already been published in the Federal Register and approved. Revoked rules have been taken out. Amended rules have been changed.
When you want to see what the current regulations are, go here. Use the subject index in the last volume to find regulations on your topic, or use the CFR section given in a relevant rule from the Federal Register.
Final rules from the Federal Register get put in the CFR. The CFR sections stay updated, incorporating the additions and changes made along the way.
Fifty volumes, updated periodically:
Updates the Code of Federal Regulations.
Contains background information that the CFR will not have for each regulation: reasons, intent, costs and benefits, invitation for comments, etc.
Arranged by agency. Know who the agencies are who affect your business, so you can browse the table of contents for any possible rules they are making.
For each agency
Notices of rules or hearings
Back contains list of CFR sections affected.