The present first volume includes the Introduction, the First Part, which is dedicated to contracts aimed at disposal (sale, donation, parental provision), and the Second Part with contracts for the provision of use. Specifically, the law of sale is also interpreted based on laws 3043/2002 (for the liability of the seller), 2251/1994 (for consumer protection), and 2532/1997 (for international sale of goods). The sale of real estate, cars, businesses, rights, as well as special types of sales (with reservation of ownership, with trial, preferential, with agreement of offsetting, with auction) are also examined in detail. In addition to common leasing, special chapters are dedicated to professional leasing, residential and family housing leasing, leases for housing services of the Public or Legal Entities, as well as financial (Leasing) and time-sharing leasing. The volume concludes with new forms of contracts for the provision of use, such as the patent license agreement, the trademark and distinctive title license agreement, the intellectual property exploitation agreement, and the technology transfer agreement (Know-how). Detailed indexes (alphabetical and legislative provisions) complete the volume.