After all is said and done, Mildred Norman Ryder Lamb AKA"Peace Pilgrim" was the first woman thru-hiker of the A.T. -- just not the first woman solo thru-hiker.

Dick Lamb was not her husband at the time of the hike. She and her first husband, Stanley Ryder, were divorced in 1946. When she hiked the AT in 1952 with Dick Lamb, they were not married. I believe they were married later on, but then divorced at some point. So when some sources refer to her as "Mildred Lamb" and to him as "her husband," it was, actually, not true at the time of the hike -- only later on.

Here are some sources:

"In 1952, the year before she began the pilgrimage, Peace Pilgrim, then known as Mildred Norman Ryder, set out on another memorable journey. On April 26th of that year, in the company of fellow Philadelphian Richard Lamb, Mildred began the 2050 mile walk north from Mt. Oglethorp in Georgia toward Mt. Katahdin, in northern Maine. By the time she completed the journey in October of that year she would become the first woman to walk the entire length of the Appalachian Trail in one season."
Source: http://www.peacepilgrim.net/ap_trail.htm and http://www.peacepilgrim.net/htmfiles/mdppbio.htm

"The first woman to complete the AT was Mary Kilpatrick. She did it in a series of hikes with her husband and finished in 1939. Mildred Lamb and her husband hiked the trail in 1952; did it as a flip-flop. She was the first woman thru-hiker. Grandma Gatewood was the first to solo thru-hike in 1955. She did it again in 1957.
Dorothy Laker was the second to solo thru-hike (1957, 1964). She was in her early 20s the first time."
Source: Hiking the Appalachian Trail, Vol. 1, Rodale Press. 1975.

"In 1955, Emma "Grandma" Gatewood became the first woman to hike the trail alone and in one continuous trip. Two years later, Dorothy Laker became the second. Oddly enough, they were also the first people to do a second thru-hike, both finishing with three two-thousand-mile trips. Not until the seventies would another woman hike the trail alone. The first woman to hike the trail in sections was Mary Kilpatrick who hiked with her husband and friends and finished in 1939. Mildred Lamb, who like Mary was from Philadelphia, hiked the trail in 1952 with her husband, Dick. They hiked from Mount Oglethorpe to the Susquehanna River, then jumped to Katahdin and hiked south. This was also the first "flip-flop," hiking the complete trail in different directions instead of in one continuous line."
Source: Walking the Appalachian Trail By Larry Luxenberg. 1994

"Mildred Lamb, in 1952, became the first woman to thru-hike the trail, hiking initially northward with her husband to the Susquehanna River and then, after taking motorized transportation to Mount Katahdin, walking southward back to Pennsylvania."
Source: The Appalachian Trail: a visitor's companion By Leonard M. Adkins. 1998.

The First 2,000 Milers
1. Myron Avery 1936
2. Max Gordon* 1936
3. Seymour Dorfman* 1936
4. Louis Zisk* 1936
5. Name unknown* 1936
6. Name unknown* 1936
7. Name unknown* 1936
8. Dr. George Outerbridge 1939
9. Dr. Mary Kilpatrick 1939 [1st woman section hiker]
10. Dr. Martin Kilpatrick 1939
11. Orville Crowder 1939
12. Charles Hazelhurst 1946
13. Earl Shaffer* 1948
14. Dr. Robert Sosman 1948
15. Carl Jones 1951
16. Eugene Espy* 1951
17. Chester Dziengielewski* 1951
18. Barton Papendick* 1951
19. George Miller* 1952
20. Richard Lamb* 1952
21. Mildred Lamb* 1952 [1st woman thru-hiker]
22. Emma Gatewood* 1955 [1st solo woman thru-hiker]
23. Emma Gatewood* 1957
24. Dorothy Laker* 1957 [2nd solo woman thru-hiker]
25. William O. Douglas 1958
*Thru Hiker

Source: The Long Distance Hiker: The Newsletter of the Appalachian Long Distance Hikers Association. Volume 11, Number 3, Summer 2000 [Linda Patton added the bold type and the notes in brackets for clarity.]