Section 3101. Scope of disclosure

(a)  Generally.  There shall be full
  disclosure of all matter material and necessary in  the  prosecution  or
  defense of an action, regardless of the burden of proof, by:
    (1)  a party, or the officer, director, member, agent or employee of a
  party;
    (2) a person who possessed a cause of action or  defense  asserted  in
  the action;
    (3)  a person about to depart from the state, or without the state, or
  residing at a greater distance from the place of trial than one  hundred
  miles,  or  so  sick or infirm as to afford reasonable grounds of belief
  that he or she will not be  able  to  attend  the  trial,  or  a  person
  authorized  to practice medicine, dentistry or podiatry who has provided
  medical, dental or podiatric care or diagnosis to  the  party  demanding
  disclosure, or who has been retained by such party as an expert witness;
  and
    (4) any other person, upon notice stating the circumstances or reasons
  such disclosure is sought or required.
    (b)  Privileged  matter. Upon objection by a person entitled to assert
  the privilege, privileged matter shall not be obtainable.
    (c) Attorney's work product. The work product of an attorney shall not
  be obtainable.
    (d) Trial preparation.
    1. Experts. (i) Upon request, each party shall  identify  each  person
  whom  the  party expects to call as an expert witness at trial and shall
  disclose in reasonable detail the subject matter on which each expert is
  expected to testify, the substance of the facts and  opinions  on  which
  each  expert  is  expected to testify, the qualifications of each expert
  witness and a summary of the grounds for each expert's opinion. However,
  where a party for good cause shown retains  an  expert  an  insufficient
  period  of  time  before  the  commencement of trial to give appropriate
  notice  thereof,  the  party  shall  not  thereupon  be  precluded  from
  introducing  the  expert's  testimony  at the trial solely on grounds of
  noncompliance with this paragraph. In that instance, upon motion of  any
  party,  made before or at trial, or on its own initiative, the court may
  make whatever order may be just. In an action  for  medical,  dental  or
  podiatric malpractice, a party, in responding to a request, may omit the
  names  of  medical, dental or podiatric experts but shall be required to
  disclose  all  other  information  concerning  such  experts   otherwise
  required by this paragraph.
    (ii)  In  an  action for medical, dental or podiatric malpractice, any
  party may, by written offer made to and served upon  all  other  parties
  and  filed  with  the  court, offer to disclose the name of, and to make
  available for examination upon oral deposition,  any  person  the  party
  making  the  offer expects to call as an expert witness at trial. Within
  twenty days of service of the offer, a party shall accept or reject  the
  offer  by  serving  a  written  reply upon all parties and filing a copy
  thereof with the court. Failure to serve a reply within twenty  days  of
  service  of  the  offer shall be deemed a rejection of the offer. If all
  parties accept the offer, each party shall be required to produce his or
  her expert witness for examination upon oral deposition upon receipt  of
  a  notice  to  take  oral  deposition in accordance with rule thirty-one
  hundred seven of this chapter. If any party, having made or accepted the
  offer, fails to make that party's expert available for oral  deposition,
  that  party  shall  be  precluded  from offering expert testimony at the
  trial of the action.
    (iii) Further disclosure concerning  the  expected  testimony  of  any
  expert  may  be  obtained  only by court order upon a showing of special
  circumstances and subject to restrictions as  to  scope  and  provisions

  concerning fees and expenses as the court may deem appropriate. However,
  a  party,  without  court  order,  may  take  the  testimony of a person
  authorized to practice  medicine,  dentistry  or  podiatry  who  is  the
  party's  treating or retained expert, as described in paragraph three of
  subdivision (a) of this section, in which event any other party shall be
  entitled to the full disclosure authorized by this article with  respect
  to that expert without court order.
    2.  Materials.  Subject  to  the  provisions  of paragraph one of this
  subdivision, materials otherwise discoverable under subdivision  (a)  of
  this  section and prepared in anticipation of litigation or for trial by
  or for another party, or by or for  that  other  party's  representative
  (including  an  attorney,  consultant,  surety,  indemnitor,  insurer or
  agent), may be obtained only upon  a  showing  that  the  party  seeking
  discovery  has  substantial  need of the materials in the preparation of
  the case and is unable without undue hardship to obtain the  substantial
  equivalent of the materials by other means. In ordering discovery of the
  materials  when  the  required  showing  has  been made, the court shall
  protect against  disclosure  of  the  mental  impressions,  conclusions,
  opinions  or  legal theories of an attorney or other representative of a
  party concerning the litigation.
    (e) Party's statement. A party may obtain a copy of his own statement.
    (f) Contents of insurance agreement. A party may obtain  discovery  of
  the  existence  and  contents of any insurance agreement under which any
  person carrying on an insurance business may be liable to  satisfy  part
  or  all of a judgment which may be entered in the action or to indemnify
  or reimburse for payments made  to  satisfy  the  judgment.  Information
  concerning  the  insurance  agreement  is  not  by  reason of disclosure
  admissible in evidence at trial. For purpose  of  this  subdivision,  an
  application  for  insurance shall not be treated as part of an insurance
  agreement.
    (g) Accident reports. Except as  is  otherwise  provided  by  law,  in
  addition  to  any other matter which may be subject to disclosure, there
  shall be full disclosure of any written report of an  accident  prepared
  in the regular course of business operations or practices of any person,
  firm, corporation, association or other public or private entity, unless
  prepared  by  a  police or peace officer for a criminal investigation or
  prosecution and disclosure would interfere with a criminal investigation
  or prosecution.
    (h) Amendment or supplementation of responses. A party shall amend  or
  supplement  a  response  previously  given  to  a request for disclosure
  promptly upon the party's  thereafter  obtaining  information  that  the
  response  was  incorrect  or incomplete when made, or that the response,
  though correct  and  complete  when  made,  no  longer  is  correct  and
  complete,  and  the  circumstances  are  such that a failure to amend or
  supplement the response would be materially misleading.  Where  a  party
  obtains  such  information  an  insufficient  period  of time before the
  commencement of trial appropriately to amend or supplement the response,
  the party shall not thereupon be precluded from introducing evidence  at
  the  trial  solely on grounds of noncompliance with this subdivision. In
  that instance, upon motion of any party, made before or at trial, or  on
  its  own  initiative,  the  court  may  make whatever order may be just.
  Further amendment or supplementation may be obtained by court order.
    (i)  In  addition  to  any  other  matter  which  may  be  subject  to
  disclosure,  there  shall  be full disclosure of any films, photographs,
  video tapes or audio tapes, including transcripts or memoranda  thereof,
  involving  a  person  referred to in paragraph one of subdivision (a) of
  this section.  There  shall  be  disclosure  of  all  portions  of  such
  material,  including  out-takes, rather than only those portions a party

  intends to use. The provisions of this subdivision shall  not  apply  to
  materials  compiled  for  law enforcement purposes which are exempt from
  disclosure under section eighty-seven of the public officers law.