Criminal conspiracy has four elements, each of which the prosecution must prove beyond a reasonable doubt. Under the law, a conspiracy occurs when there is an agreement between at least two parties to achieve an illegal goal, with the parties possessing knowledge of and engaging in participation in the conspiracy; and at least one conspirator having committed an overt act in furtherance of the conspiracy. A conspiracy is distinct from the substantive crime contemplated by the conspirators and may be charged whether or not the substantive offense envisioned by the conspiracy occurred. Although acquittal on a conspiracy charge does not bar prosecution based on the substantive offense, acquittal on the substantive offense may bar conviction on the conspiracy count. Regarding defenses to a conspiracy charge, they are discussed under the following topical labels: statute of limitations, variance, multiplicitous indictment, insufficient indictment, and withdrawal, in addition to failure to prove some element required for a conspiracy to occur. Other defenses mentioned are insanity and coercion or duress. Conspiracy trial prosecutors often include testimony by co-conspirators in order to ensure a conviction. One section of the article discusses the co-conspirator exception to the hearsay rule. The discussion addresses evidentiary issues and sixth amendment concerns regarding the right to confront witnesses at trial. Other portions of the article discuss vicarious liability, joinder and severance, acquittal of other co-conspirators, and sentencing. 171 footnotes