Recommended Readings
Moran JV, Holmes SE, Naas TP, DeBerardinis RJ, Boeke JD, & Kazazian HH, Jr. High frequency retrotransposition in cultured mammalian cells. Cell 87, 917-927 (1996). PMID: 8945518. First demonstration of L1 retrotransposition in cell culture
Szak ST, Pickeral OK, Makalowski W, Boguski MS, Landsman D, & Boeke JD. Molecular archeology of L1 insertions in the human genome. Genome Biol 3, research0052 (2002). PMID: 12372140. Detailed account of L1 characteristics in our genome
Han JS & Boeke JD. A highly active synthetic mammalian retrotransposon. Nature 429, 314-318. (2004) PMID: 15152256. The genesis of a synthetic L1, later known as ORFeus
Hancks DC, Kazazian HH Jr. Active human retrotransposons: variation and disease. Curr Opin Genet Dev. 22(3):191-203 (2012).PMID: 22406018. A comprehensive catalog of sporadic diseases caused by human retrotransposons
Rosser, J.M. & An, W. L1 expression and regulation in humans and rodents. Front Biosci. E4:2203-25 (2012). PMID: 22202032. (licensed 
here ). Our own review on L1 expression and regulation.
Bao J, Yan W. Male germline control of transposable elements. Biol Reprod. 86(5):162, 1-14 (2012). PMID: 22357546. A recent review of retrotransposon regulation in the male germ line
Sedivy JM, Kreiling JA, Neretti N, De Cecco M, Criscione SW, Hofmann JW, Zhao X, Ito T, Peterson AL. Death by transposition - the enemy within? Bioessays. 35(12):1035-43 (2013). PMID: 24129940. A recent review of the role of retrotransposition in cellular senescence and aging
Carreira PE, Richardson SR, Faulkner GJ. L1 retrotransposons, cancer stem cells and oncogenesis. FEBS J. 281(1):63-73 (2014). PMID: 24286172. A recent review of the role of retrotransposition in oncogenesis
Volkman HE, Stetson DB. The enemy within: endogenous retroelements and autoimmune disease. Nat Immunol. 15(5):415-22 (2014). PMID: 24747712. A recent review of the role of retrotransposition in autoimmune diseases
Erwin JA, Marchetto MC, Gage FH. Mobile DNA elements in the generation of diversity and complexity in the brain.Nat Rev Neurosci. 15(8):497-506 (2014). PMID: 25005482. A recent review of the role of retrotransposition during neurogenesis and in neurological disorders
And, of course, many more can be found by a PubMed Search.