Eldred v. Bell Telephone Company was a case heard by the United States Supreme Court in 1885. The case involved a dispute between the Bell Telephone Company and the Eldred family over the ownership of a patent for a telephone transmitter. The Eldreds claimed that they had invented the transmitter and had applied for a patent for it, but the Bell Telephone Company had obtained a patent for the same invention. The Eldreds argued that the Bell Telephone Company had infringed upon their patent rights and sought damages. The Supreme Court held that the Bell Telephone Company had not infringed upon the Eldreds' patent rights. The Court reasoned that the Eldreds had not obtained a patent for their invention before the Bell Telephone Company had obtained a patent for the same invention. Therefore, the Court held that the Bell Telephone Company had not infringed upon the Eldreds' patent rights. The Court's decision in Eldred v. Bell Telephone Company established the principle that a patent is only valid if it is obtained before another party obtains a patent for the same invention. This principle is still applied today in patent law.

Justice Field delivered the dissenting opinion in Eldred v. Bell Telephone Company, arguing that Congress had exceeded its authority under the Constitution when it granted a patent to Alexander Graham Bell for his invention of the telephone. He argued that while Congress has broad powers over patents and copyrights, these powers are limited by Article I Section 8 of the Constitution which states that such grants must be "for limited times." Justice Field believed that granting an indefinite monopoly on an invention was not within this power and thus unconstitutional. Furthermore, he argued that allowing such monopolies would create economic inequality as only those with money could afford to pay for them or benefit from them. Finally, he contended that if Congress were allowed to grant unlimited monopolies then inventors would have no incentive to innovate since they could never reap any rewards from their inventions due to perpetual competition-free markets created by government-granted monopolies.