The short answer
Written discovery is how parties exchange information on paper. Interrogatories are written questions answered under oath. Document requests seek records. Requests to admit ask a party to admit specific facts.
Where it fits in your case
Usually the first discovery served. Responses are generally due within 28 days in Illinois state court and 30 days in federal court.
What to expect
Interrogatories are generally limited to 30 in Illinois (Rule 213) and 25 in federal court.
Document requests reach emails, texts, and electronic files, not just paper.
Requests to admit are deemed admitted if not answered on time (Rule 216).
What we need from you
Prompt access to records and people, and a careful review of draft answers, since you sign them under oath.
Common misconceptions
“A missed request to admit is minor.” It can establish a fact against you.
“Our lawyer answers for us.” Interrogatory answers are your sworn statements.