from H. P. Lovecraft to Clark Ashton Smith: in his Selected letters Vols. 2 to 5

193: September 1, 1925: II.25
196: September 20, 1925: II.26
197: October 9, 1925: II.27
202: December 27, 1925: II.32
207: February 9, 1926: II.38
217: May 14, 1926: II.49
223: June 17, 1926: II.57
228: August 8, 1926: II.62
239: October 12, 1926: II.76
243: October 29, 1926: II.89
245: November 16, 1926: II.90
251: December 11, 1926: II.94
257: January 21, 1927: II.98
260: February 18, 1927: II.103
263: March 15, 1927: II.113
264: March 42, 1927: II.114
271: May 12, 1927: II.127
277: June 3, 1927: II.140
282: June 24, 1927: II.148
286: July 15, 1927: II.154
290: August 2, 1927: II.159
298: October 1, 1927: II.173
301: October 15, 1927: II.176
307: November 27, 1927: 201
318: January 31, 1928: II.223
326: April 19, 1928: II.237
332: August 31, 1928: II.246
350: March 22, 1929: II.327
351: April 14, 1929: II.328
373: October, 1929: III.29
383: December 3, 1929: III.87
387: December 19, 1929: III.95
394: January 17, 1930: III.111
398: February 2, 1930: III.116
400: February 27, 1930: III.119
401: March, 1930: III.119
423: September 11, 1930: III.168
424: September 24, 1930: III.168
429: October 7, 1930: III.185
431: October 17, 1930: III.192
436: October 31, 1930: III.203
439: November 7, 1930: III.216
441: November 18, 1930: III.218
446: November 29, 1930: III.238
449: December 25, 1930: III.242
452: January, 1931: III.247
462: February 8, 1931: III.286
470: March 26, 1931: III.356
497: September 11, 1931: III.411
511: November 20, 1931: III.435
522: January 28, 1932: IV.9
523: January 29, 1932: IV.10
529: February 18, 1932: IV.18
531: February 26, 1932: IV.23
533: March 2, 1932: IV.25
543: April 4, 1932: IV.37
556: July 26, 1932: IV.51
576: October 28, 1932: IV.98
584: December 5, 1932: IV.115
604: February 18, 1933: IV.155
615: April 8, 1933: IV.179
622: May 31, 1933: IV.200
627: June 14, 1933: IV.212
630: June 29, 1933: IV.217
644: September 11, 1933: IV.241
652: October 3, 1933: IV.270
658: October 22, 1933: IV.288
666: November 13, 1933: IV.317
669: November 18, 1933: IV.319
673: November 29, 1933: IV.324
674: December 13, 1933: IV.328
685: February 11, 1934: IV.375
691: March 9, 1934: IV.391
729: September 30, 1934: V.38
735: October 28, 1934: 56
758: March, 1935: 112
766: March 26, 1935: 130

Note: portraits of Clark Ashton Smith can be found facing II.169, V.59, and V.220; artwork can be found facing II.201 and III.198.