This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
Sec. 36. Origin of general theory of contract.
Sec. 37. General nature of obligation.
Sec. 38. Parties to obligation.
Sec. 40. Money value of obligation.
Sec. 42. Promissory character of agreement.
Sec. 43. Community of intention.
Sec. 44. Intent to affect legal relations of parties thereto.
Sec. 45. Methods of entering into agreement.
Sec. 47. Quasi-contract.
Sec. 48. Classification and arrangement of topics.