DIVISION 6. WITNESSES
    CHAPTER 3. EXPERT WITNESSES
        ARTICLE 1. EXPERT WITNESSES GENERALLY
            SECTIONS 720-723

720. (a) A person is qualified to testify as an expert if he has special knowledge, skill, experience, training, or education sufficient to qualify him as an expert on the subject to which his testimony relates. Against the objection of a party, such special knowledge, skill, experience, training, or education must be shown before the witness may testify as an expert.
(b) A witness' special knowledge, skill, experience, training, or education may be shown by any otherwise admissible evidence, including his own testimony.

721. (a) Subject to subdivision (b), a witness testifying as an expert may be cross-examined to the same extent as any other witness and, in addition, may be fully cross-examined as to (1) his or her qualifications, (2) the subject to which his or her expert testimony relates, and (3) the matter upon which his or her opinion is based and the reasons for his or her opinion.
(b) If a witness testifying as an expert testifies in the form of an opinion, he or she may not be cross-examined in regard to the content or tenor of any scientific, technical, or professional text, treatise, journal, or similar publication unless any of the following occurs:
(1) The witness referred to, considered, or relied upon such publication in arriving at or forming his or her opinion.
(2) The publication has been admitted in evidence.
(3) The publication has been established as a reliable authority by the testimony or admission of the witness or by other expert testimony or by judicial notice. If admitted, relevant portions of the publication may be read into evidence but may not be received as exhibits.

722. (a) The fact of the appointment of an expert witness by the court may be revealed to the trier of fact.
(b) The compensation and expenses paid or to be paid to an expert witness by the party calling him is a proper subject of inquiry by any adverse party as relevant to the credibility of the witness and the weight of his testimony.

723. The court may, at any time before or during the trial of an action, limit the number of expert witnesses to be called by any party.

DIVISION 7. OPINION TESTIMONY AND SCIENTIFIC EVIDENCE
    CHAPTER 1. EXPERT AND OTHER OPINION TESTIMONY
        ARTICLE 1. EXPERT AND OTHER OPINION TESTIMONY GENERALLY
            SECTIONS 800-805

800.  If a witness is not testifying as an expert, his testimony in the form of an opinion is limited to such an opinion as is permitted by law, including but not limited to an opinion that is:
   (a) Rationally based on the perception of the witness; and
   (b) Helpful to a clear understanding of his testimony.

801.  If a witness is testifying as an expert, his testimony in the form of an opinion is limited to such an opinion as is:
   (a) Related to a subject that is sufficiently beyond common experience that the opinion of an expert would assist the trier of fact; and
   (b) Based on matter (including his special knowledge, skill, experience, training, and education) perceived by or personally known to the witness or made known to him at or before the hearing, whether or not admissible, that is of a type that reasonably may be relied upon by an expert in forming an opinion upon the subject to which his testimony relates, unless an expert is precluded by law
from using such matter as a basis for his opinion.

802.  A witness testifying in the form of an opinion may state on direct examination the reasons for his opinion and the matter (including, in the case of an expert, his special knowledge, skill, experience, training, and education) upon which it is based, unless he is precluded by law from using such reasons or matter as a basis for his opinion.  The court in its discretion may require that a witness before testifying in the form of an opinion be first examined concerning the matter upon which his opinion is based.

803.  The court may, and upon objection shall, exclude testimony in the form of an opinion that is based in whole or in significant part on matter that is not a proper basis for such an opinion.  In such case, the witness may, if there remains a proper basis for his opinion, then state his opinion after excluding from consideration the matter determined to be improper.

804.  (a) If a witness testifying as an expert testifies that his opinion is based in whole or in part upon the opinion or statement of another person, such other person may be called and examined by any adverse party as if under cross-examination concerning the opinion or statement.
(b) This section is not applicable if the person upon whose opinion or statement the expert witness has relied is (1) a party, (2) a person identified with a party within the meaning of subdivision (d) of Section 776, or (3) a witness who has testified in the action concerning the subject matter of the opinion or statement upon which the expert witness has relied.
(c) Nothing in this section makes admissible an expert opinion that is inadmissible because it is based in whole or in part on the opinion or statement of another person.
(d) An expert opinion otherwise admissible is not made inadmissible by this section because it is based on the opinion or statement of a person who is unavailable for examination pursuant to this section. 805.  Testimony in the form of an opinion that is otherwise admissible is not objectionable because it embraces the ultimate issue to be decided by the trier of fact.

The complete text from California Evidence Code can be found on the official site for California legislative information.