On page 289 of Jew and Gentile in the Ancient World, Louis Feldman states the following:
"In the latter part of the nineteenth and the early part of the twentieth century, much scholarship, especially in Germany, insisted that Judaism, particularly in the period after Bar Kokhba but not restricted to that period, was not interested in gaining converts. In fact, Judaism was said to be hostile to such attempts. Such scholarship was often based on hidden agenda, namely to prove that Christianity, which eagerly sought proselytes, was therefore superior to Judaism. Scholars who responded to this thesis tried either to explain away Judaism's noninvolvement in proselytism or to show that Judaism was actually inherently missionary in nature. Just prior to World War II, the Reform Judaism movement in the United States considered the possibility of seeking out converts; two works of scholarship that appeared at the time concluded that Judaism in the Talmudic period was favorably disposed toward proselytes and indeed sought after them eagerly."
Feldman then refers to George Foot Moore, who said that Jews tried to convert Gentiles to the worship of the one true God, yet did not officially send out missionaries.
Feldman also refers to Scot McKnight's (yes, the Scot McKnight) A Light Among the Gentiles: Jewish Missionary Activity in the Second Temple Period, and Martin Goodman's Mission and Conversion. Their position, according to Feldman, was that "Judaism was not at all a missionary religion during this period" (page 290). For Goodman, when Philo and Josephus talk about the spread of customs such as the Sabbath and dietary laws, the issue is Judaizing, adopting Jewish customs without actually converting. My impression is that Feldman disagrees with Goodman and argues that Judaism honored and even glorified proselytism.
It's interesting that scholars in the nineteenth-early twentieth centuries put down Judaism because it supposedly wasn't a missionary religion that sought converts. Nowadays, Judaism is praised for not being a missionary religion. I've heard Jews emphasize that their religion is not missionary, usually to distinguish themselves from evangelical Christians, who want everyone to believe like them. In this day and age, not being a missionary religion is consistent with pluralism, and perhaps post-modernism.