Continuing the first line of a contract (as in the previous blog post on made or entered into), you would typically find the word between, and sometimes amongst (or among). And if it says is made, then it is made by the parties. What should it be? Is there a right way here? (Yes, I think so.)
Use between in the introductory clause rather than amongst or a combination such as by and between. It subtly gives the agreement a more personal character, as is more consistent with the nature of contracts (i.e. reflecting the consent of two or more parties, rather than a mere bargain). Semantically, the distinction between between and amongst is not whether you refer to two parties or to three or more; it is whether you refer to one thing and another or to a collective or undefined number. Compare walk between two trees with walk among the trees.
Avoid using by for the same reason as applies to amongst; it turns an agreement into something outside the parties (i.e. the parties are the makers of a contract, being a work). Nevertheless, whether you use between or amongst does not influence the legal effect of the contract.