Long appreciated since the late 18th century (it was recommended by early Alsatian chess enthusiast Elias Stein) the Dutch Defense (1. d4 f5) has seen its fair share of troubles. In the 1930s, Siegbert Tarrasch, well-known for his rigid, "post-steinitz neoclassical" rules, asserted that White would be better after the Staunton Gambit, 1. d4 f5 2. e4 (...fxe4 3. Nc3 Nf6 4. Bg5 c6 5. f3! exf3).
Nonetheless, it has rebounded through ages. Botvinnik, for example, being himself well-versed in the French Defense, would avoid the Staunton Gambit by replying to 1. d4 with 1...e6 to transpose into the Dutch (it becomes clear in his 100 Selected Games that he was very unwilling to chance playing the Black pieces against the Staunton Gambit). But as of late, it has become less and less common at the top level. Hikaru Nakamura will use it on occasion and Loek Van Wely recently beat Aronian with it in Tata Steel.
It is not a defense for the faint of heart, and it leaves many weaknesses in the Black position. For beginners, it should be mentioned that this is not similar to a "1. d4 Sicilian". The f5 pawn will be there for a while, and thus, the Black light square bishop (LSB) will be limited. Moreover, the Queen's Knight (b8 knight) may also have trouble developing in a few lines. Despite this, it is still a fun opening for those who, ironically (considering the challenges in Queen side development) like attacks, and many great sacrificial games have come from the Dutch Defense. Here are a few games from different eras in chess that illustrates its strengths. Hopefully, I will be able to upload a few games that illustrate its weaknesses soon. Unfortunately, I haven't been able to keep up with a lot of the modern theory in the ...g6/ Leningrad Variations.