CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "direct.mit.edu",cType: 'managed',cRay: '917c8a573ccef88c',cH: 'sVYRMog6.OF4mkdrMpwGkTaoyRKMNEOVZ6K1UKA70BI-1740537311-1.2.1.1-aR3V52lgP7pG1D9vB7cq_GgHsrXj14fpVggk_OJCc9eyqnbfyVwEE.wuFotzLUKR',cUPMDTk: "\/books\/pages\/direct-to-open?__cf_chl_tk=hFsP9rcpCnxQ4AA46zCRo9q136KHfyk1LUScUPB5jgQ-1740537311-1.0.1.1-IrmipqilTKVFGwoCKlDDq5FoT3xv_3Som3UUfxo4a7E",cFPWv: 'b',cITimeS: '1740537311',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/books\/pages\/direct-to-open?__cf_chl_f_tk=hFsP9rcpCnxQ4AA46zCRo9q136KHfyk1LUScUPB5jgQ-1740537311-1.0.1.1-IrmipqilTKVFGwoCKlDDq5FoT3xv_3Som3UUfxo4a7E",md: "O1.267H7UeQUMEffoF95nzA.nhHodWxN33iQWzY2fIQ-1740537311-1.2.1.1-uvdlPbO.S1EaV9bGNYN69K4nPJd50f6CrrAoH2qlq21u9.Cu6aK0sMUge5hKjL7vCWTV0NaZ_MI4mBTjkWgD67UoL3D57d7bnqzpXkjKBSb6wSEOHec.eODvkqMSoAMehjxOkkrK.FSc8pR9KpbvZa5JeZ0Tv7v1K29OoWb3ecP2e6Z3WAR8.TmuWFzlOj0TMEEslpmgMF889Lqx6TVZiRHzfMI.ek6P6e0BSiTrkRGPmIV2oGkOiQqYEIAW1HBtHM74TYWDPAq6jOHJmFRU0sT30brxWrGkLoLvTIaLJxAvFZydtGKuBoJ2h3G37qsHM7O0qCAXm_om9QSqfTyy3LheXbRmVinsucVTCuv05NDqjEI5.9z5gXrDjEVwpFBcqrvfjZiChfbfAviZuw6MxrlH8ZkSZS_bGFGO9P3OAXuyL4WSZNtBnz1xrLzCVhLNjp.9NAB6_FgB8OPl_RpYgOb9eWJMMKWS_d3c1oSXSkpmfje9FSkcpVYeBG99J9WhX89GBDwDX35N8_ehxb67u_6v32tNhP4.0OOtwRiZuFYDJZlxUMyUnm3svR56jX7bxxzrYSL5C1pRSvT3SC7VrJ88M7YlUp8PrHyzWo033mqGcR4KWVJvx0H71TPmT_.zqn8kr6rT6tcI0HQp8iHG8q_gXSe1k7uuVPHdgnD7SXSOrXKcLirrX.D_l9aWZnWBisTRckzrRHEazllJW9sjWn7tpJzRkJoFjorg3B.I22cKzyZZZxk7kBQWWj1iUeAfMHIuv1VZ_bRgEtYFAaEeSrbMVLilEGoegGn8LKZoSL8mx01l631BO8LH5efU7ioJ8rShftQ3whu4HMqvOHOEKxAtEL4Tq_XgHPvgaMrtAdNBsgeo6DX36aunGvuHaw3jlgFBjvkz.Soulxxbcg3IIMY9A5SENxsJoQQoPIaJYycXWq1y.LwqK9P5qZrMbuIX2FxfOYUaR_04PWCZ3SDrUQfzVRa3tAqxA3g_gTcr0Ifhrr6j37igq3zDpijGuIMoDfHTWRCKgve6TEgn3pZCCKoYqdZFqQlqneU_LLnQgTpq1LRK1L2yCusnRdIpbl2p2skgyajxw5sA5Q.uARkfnGV.ekf4TalhQS61GbPJS_OqAgI4bEW_x6HNQGqLbsCX79_uQKMBn1d.HSNv5EVCjn_UBenJPfQeN3Fc0yQtklQXhrJiwHeYQEKSYZcQx4F4uy9gAD7fwSAKYB29x87h93.YI4SJuRK4IvNqqNyfKkWl5F0lyVwxkxSRqaefa9nYIg.jOus_Okzpn8G3mTxs0k1zUjbcbfTcDqDliWslk10XwYLDccbbHJiTrwODu.EtlMoZHbhLOshzv2PPnw_BkFqZ9t9MVxIrkpII5ivG16OveHUUFO4NoSqc9YvxEGntfRytsebvAZKs1q3GgyW4bnt86p.uT3Qg1K8lGBviWaUSnFo2.Ll_pgCsLCMosIMEMoiz_cMgoEEKEfCpbf4ucVd3rEogQ1B15aaqeVg4yHvGHMpv6dz0lCtw18oLDFDBUgN9MVH3PqN.TUV1jVr5LHMmK5IG9bs1hqlzLu.D5OsoekpuqEta0Nqjg1ARQZCP8DQDRnVMHl2K8ZI2Z4tNaMTiodquJcXaE4n7hrK3IhUnJ7nt1iAdbW2HEIlAE9e1jnB3sgQNAxVu3T2a9aXa9Nra8BQC5of_3j4HQyBIuyEhaULlPu3XHHJ9eLD.i.5iOs40X05JwZL7wSXZ5zzbfa.Ae4F9aQNLdnKYko3wxM8mExm4QmwjNpiXfO_LwSAt4gl_PGknbIW7eL3WaPJtIAD5mBEM7zDzvkkeRgqs0.rKAEqtkByHb1vQ31u46QbkfOPHszyYGi1pmF00BDCqGEWeAKR8Mi65SUGcu.cGsmeCdraM18F1XjZKs6FzbiY2wpkyMhMukyh0KdwmRmIMq15KqUuuz.G30yBv.c3pxRoI5yHwuwDJLv.T4OIZikTPxsXriqedQeB6Gs6IvvAuGyzSHLFEwVf9Z43Th7FGUyxpkeL3hB1PiuN1zJjcJvSkZrkG5ssfFW42bL9QIthwgsMyOMh59plKIK3Wx6ERkNYkMfJIX48JGV1_A6lQpVjN_8TrXaLNF9PpyL_x72itcKiMQzKHHy918TubjhqxMWT_75fVW1rr7uCH2BtSRbJS6kVu7iphJeLmIK_kPpXeglYc6H7HRJLSTfK_Iayy39roIqoseRun5hDwnSz3KHa5fRyATk_F8NId9_YZmrleZReBQY96EfitcDLiYc2qvhd7oTs4ld2jvjI6_BEUi4NbwOcqW3Ob7735Aa1C.NMPW1oQhDY11WVg9wkvtDmxZL7kPg10kvL2PxnZIr2g58rL3vaq5AJ8WGTrURFCD8z90m.nbcz9hK3RiaNgmVN0Z6CF7KX1kxOP0zPhLPHmkU9Rxlcn2ddtAPTFIJxgLXS0G3mg9tdcX4yeEdgpy5WDAFry7_dVvr2Nhbrgk.LjKNui2ZEdKp65_49tDm6_mM5.TPQtJfdIaTv04OoVx8UjkFteQ3kC7eUJ0QqE7NkqyaeCsLQheytNTkdN7t5zPcrpZA",mdrd: "IYdOKDSlr0F8BbAEI2ooXN0QEbo9OLA0DhFAy5nhTK8-1740537311-1.2.1.1-jLOg83AXZmFrlLUQlpDhP.V_iaf597qjqPkBJVKIcTjQyWsW9PQtXB3IpEML8oKJEA9LJHSizJJuxBliIOrTnXuTm0b9uMLG9n1jpuqyt746PtffuGeIVTOLVSkRVSlP_7VnP.Y7nbxBJvK6a0zYjxb0dravgf99vwaLMxj5Q2j0.rmgkQeOCw5NrUe6WUnx9FCoKgmzOwfBOg1IXuvNrIRtw3xPEU1vdw2gxspwdQlVvoRpD8YJW7oA8Pzclco9Cg7wIm8fyPppi0J.2hF79nLS4RIu5bA3BSK5TLAICbpUAQOF8ohMMOgyxEDFNP5sVf4AN.7bxpVYjHkKrc54WBfFww0RsM5w0dAZT2JY3Y4Yn5CjV0e0aku_FxgvsXqs4NQ9GCZHzyUlN9Wf.k.gxjXdl_vsaaI7mvyx3KYCn8Oi9kAMEdJ8b2PUp4XG5MqRrXO2yR5mDQay2PkMwAkooqKdhYpIwjX8vDX24YkaLLrmMnQaEsn6Snr7Ra2gjfE_WwQn5YKCjQWKdvKJtvW5.yXvrKhRFyLotIMS.iemKdy.4MxuMzSHCZGDFvzzdUTn1CDu3UosfbSlxCWgTA_TLW9Icidh3MNfbG2SuHPOU1KHMihrN8K38SOjhAlPpD54.DpatI6nxvaXrrUruMXKNuFTdnL52L5UU1_7u3SWBSokrj9r0C24sqqA_.VlpqQK2OWR.08ixM_UcCZn6EtfIPgeVX9rNAWrtNXGi5qcvOqpzSuNnr7hsevO8RLzOVEAr7n8ZUNbPCNFXDIYQaWKu0e90OgSDEO2EEOlXI.cybq5c73IbpVgKFgbCZ._9ZOWDos0Sp7NDX8k_xr4CMLhFeQcyvTfkbscL3Jn.tc7c20XriXWs1ETpigRVZZVFWGV5Pq87Y6ffD_BZ6xmFWUtzXgVnwHZ1YOghFKyYfm22ytChlMTXDiU9zEssNBx4w3jUtn8n7smKIkwGrWuKRA3nShDAdhK.iL.8J2M3kd4PBsD9LE026tiYbCjWj2KhXv_20qlDF0_e3TkHla6EnGfZ.O7330bFYVw0GiYPZVw.Xyu4Jd2ouSidGU4tYWTsuUo3UgEA_KfSRfKmkoy9RtAM.zlKy.pDSNf3IZkl_mdLZyCfh_HFXPfAtXIs6LGc3SH1om79L0Yk7N8g1NBBClN2vQJwQKf7s1xfoiqo0SqDCC8ruP_AAaUKWqav.AG9v.BYJV9Q.JSZR9DwSQrX2wlTjNaoEdwpY2MiUtrT4aU6XgoQ1jCbJWfQ4KAxJxb8kh2Vv.tuSfgkeXgF5_ZWgjPnVXjJjRMG8gf9Wyc.fqxWhYUaMQzLJVd75007h4hTupStESgmmMJH_Z5RnxHZ.bxlYLpMjHCmchgidtbq5u6q8zZYOIcSo4TCh27McvkiLz7ghz5.YWXQj4oo3swhqKSrSrssjxJ03EDZpA95_4HqlLpRVyPjdjlaHJFPwXPGJOS7D4flWWPxsLZ7euDnfYeRD4ASw8sYSUqakkUmfIhj1dYAs9pynAl_BAw.AfEdMeo9X1gtvaiHHDmFzb8RKyze3w359wNEVGZoadNZ1ydopC6ccl6wmvvFNcx1Va7CMnB.dxQcDpyFV.pdbIN4LQ1AwgZI0mekWQ_TyxqMmZAPBh7NBWiZ3h9GvjnwZ3WgE2WEA2GxT2EK_jdGqlPut5_1liT0a_i_yx7wMfRdI8dGppAxQSEMdUJVXvaRKJkxEauEkuAFg65Ck7in1HnlBRned7O.9SnD4c4VVtg0pQ43iKF8i9jVwYtRsI9ET.U63jVEJb0JDN8O.26uAsOihLFHUm86yE9H3eqPzwsSISDAkylzuKXHwTrWoy0vcVYctv.wf59.v_.3RvxG8zPlz7kYzNEyb9jOcC.4qxmBtzN6.XO78rNdIs1gQ5GOpX7lSj5jZwZCRhpQ9PITmXosG_Y6kvM2A5uZ_pVdHumFQV5Mq6npgukPOhhgvD8hlawrXSf"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=917c8a573ccef88c';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/books\/pages\/direct-to-open?__cf_chl_rt_tk=hFsP9rcpCnxQ4AA46zCRo9q136KHfyk1LUScUPB5jgQ-1740537311-1.0.1.1-IrmipqilTKVFGwoCKlDDq5FoT3xv_3Som3UUfxo4a7E" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>