Short answers, pulled from the story.
One theory suggests the name means very steadfast or unbowed based on a compound word combining elements meaning very much and to stay or stand fast. Another view proposes the name developed from an unattested form meaning very mindful while a third proposal derives the second part from a root meaning to be inclined or to strive eagerly.
Agamemnon descended from Pelops son of Tantalus with his father being Atreus who murdered the sons of his twin brother Thyestes. This family line included Thyestes' daughter Pelopia who bore Aegisthus to vow gruesome revenge on Atreus children.
Preparing to depart from Aulis a port in Boeotia Agamemnon's army incurred the wrath of Artemis which could only be propitiated by sacrificing Agamemnon's daughter Iphigenia. Some versions claim she was tricked into believing she would marry Achilles before her death while other sources say Artemis accepted a deer in her place and whisked her away to Tauris in the Crimean Peninsula.
According to Pindar and tragedians Agamemnon was killed in a bath by his wife Clytemnestra who ensnared him with a blanket or net thrown over him to prevent resistance. Her motivations included wrath at the sacrifice of Iphigenia and jealousy of Cassandra before Aegisthus and Clytemnestra ruled Agamemnon's kingdom for a time.
Heinrich Schliemann discovered the Mask of Agamemnon in 1876 and it now resides on display at the National Archaeological Museum in Athens. The mask bears considerable resemblance to representations of Zeus found throughout Greek art and connects legendary figures to tangible historical evidence from the Bronze Age.