An isolated antibody that binds to CD33, wherein the antibody comprises: (i) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:8; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:9; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:10; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:5; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:6; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:7; or (ii) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 11; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 12; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:13; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:5; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:6; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:7; or (iii) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:20; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:21; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:22; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:5; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:6; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:7; or (iv) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:39; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:40; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:41; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:36; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:37; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:38; or (v) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:45; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:46; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:47; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:42; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:43; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:44; or (vi) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:56; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:57; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:58; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:53; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:54; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:55; or (vii) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:62; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:63; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:64; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:59; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:60; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:61. (i) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:8; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:9; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:10; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:5; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:6; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:7; or (ii) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 11; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 12; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:13; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:5; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:6; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:7; or (iii) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:20; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:21; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:22; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:5; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:6; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:7; or (iv) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:39; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:40; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:41; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:36; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:37; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:38; or (v) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:45; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:46; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:47; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:42; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:43; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:44; or (vi) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:56; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:57; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:58; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:53; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:54; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:55; or (vii) (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:62; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:63; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:64; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:59; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:60; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:61.